In the Linux kernel, the following vulnerability has been resolved: bpf: Fix reference state management for synchronous callbacks Currently, verifier verifies callback functions (sync and async) as if they will be executed once, (i.e. it explores execution state as if the function was being called once). The next insn to explore is set to start of subprog and the exit from nested frame is handled using curframe > 0 and prepare_func_exit. In case of async callback it uses a customized variant of push_stack simulating a kind of branch to set up custom state and execution context for the async callback. While this approach is simple and works when callback really will be executed only once, it is unsafe for all of our current helpers which are for_each style, i.e. they execute the callback multiple times. A callback releasing acquired references of the caller may do so multiple times, but currently verifier sees it as one call inside the frame, which then returns to caller. Hence, it thinks it released some reference that the cb e.g. got access through callback_ctx (register filled inside cb from spilled typed register on stack). Similarly, it may see that an acquire call is unpaired inside the callback, so the caller will copy the reference state of callback and then will have to release the register with new ref_obj_ids. But again, the callback may execute multiple times, but the verifier will only account for acquired references for a single symbolic execution of the callback, which will cause leaks. Note that for async callback case, things are different. While currently we have bpf_timer_set_callback which only executes it once, even for multiple executions it would be safe, as reference state is NULL and check_reference_leak would force program to release state before BPF_EXIT. The state is also unaffected by analysis for the caller frame. Hence async callback is safe. Since we want the reference state to be accessible, e.g. for pointers loaded from stack through callback_ctx's PTR_TO_STACK, we still have to copy caller's reference_state to callback's bpf_func_state, but we enforce that whatever references it adds to that reference_state has been released before it hits BPF_EXIT. This requires introducing a new callback_ref member in the reference state to distinguish between caller vs callee references. Hence, check_reference_leak now errors out if it sees we are in callback_fn and we have not released callback_ref refs. Since there can be multiple nested callbacks, like frame 0 -> cb1 -> cb2 etc. we need to also distinguish between whether this particular ref belongs to this callback frame or parent, and only error for our own, so we store state->frameno (which is always non-zero for callbacks). In short, callbacks can read parent reference_state, but cannot mutate it, to be able to use pointers acquired by the caller. They must only undo their changes (by releasing their own acquired_refs before BPF_EXIT) on top of caller reference_state before returning (at which point the caller and callback state will match anyway, so no need to copy it back to caller).

The AlmaLinux 9.2 host has packages installed that are affected by multiple vulnerabilities as referenced in the TuxCare ALMALINUX9.2:CLSA-2026:1786761805 advisory.

  - A flaw was found in the KVM's AMD nested virtualization (SVM). A malicious L1 guest could purposely fail     to intercept the shutdown of a cooperative nested guest (L2), possibly leading to a page fault and kernel     panic in the host (L0). (CVE-2022-3344)

  - In the Linux kernel, the following vulnerability has been resolved: usbnet: Run unregister_netdev() before     unbind() again Commit 2c9d6c2b871d (usbnet: run unbind() before unregister_netdev()) sought to fix a     use-after-free on disconnect of USB Ethernet adapters. It turns out that a different fix is necessary to     address the issue:
    https://lore.kernel.org/netdev/18b3541e5372bc9b9fc733d422f4e698c089077c.1650177997.git.lukas@wunner.de/ So     the commit was not necessary. The commit made binding and unbinding of USB Ethernet asymmetrical: Before,     usbnet_probe() first invoked the ->bind() callback and then register_netdev(). usbnet_disconnect()     mirrored that by first invoking unregister_netdev() and then ->unbind(). Since the commit, the order in     usbnet_disconnect() is reversed and no longer mirrors usbnet_probe(). One consequence is that a PHY     disconnected (and stopped) in ->unbind() is afterwards stopped once more by unregister_netdev() as it     closes the netdev before unregistering. That necessitates a contortion in ->stop() because the PHY may     only be stopped if it hasn't already been disconnected. Reverting the commit allows making the call to     phy_stop() unconditional in ->stop(). (CVE-2022-49501)

  - In the Linux kernel, the following vulnerability has been resolved: crypto: arm64/poly1305 - fix a read     out-of-bound A kasan error was reported during fuzzing: BUG: KASAN: slab-out-of-bounds in     neon_poly1305_blocks.constprop.0+0x1b4/0x250 [poly1305_neon] Read of size 4 at addr ffff0010e293f010 by     task syz-executor.5/1646715 CPU: 4 PID: 1646715 Comm: syz-executor.5 Kdump: loaded Not tainted     5.10.0.aarch64 #1 Hardware name: Huawei TaiShan 2280 /BC11SPCD, BIOS 1.59 01/31/2019 Call trace:
    dump_backtrace+0x0/0x394 show_stack+0x34/0x4c arch/arm64/kernel/stacktrace.c:196 __dump_stack     lib/dump_stack.c:77 [inline] dump_stack+0x158/0x1e4 lib/dump_stack.c:118     print_address_description.constprop.0+0x68/0x204 mm/kasan/report.c:387 __kasan_report+0xe0/0x140     mm/kasan/report.c:547 kasan_report+0x44/0xe0 mm/kasan/report.c:564 check_memory_region_inline     mm/kasan/generic.c:187 [inline] __asan_load4+0x94/0xd0 mm/kasan/generic.c:252     neon_poly1305_blocks.constprop.0+0x1b4/0x250 [poly1305_neon] neon_poly1305_do_update+0x6c/0x15c     [poly1305_neon] neon_poly1305_update+0x9c/0x1c4 [poly1305_neon] crypto_shash_update crypto/shash.c:131     [inline] shash_finup_unaligned+0x84/0x15c crypto/shash.c:179 crypto_shash_finup+0x8c/0x140     crypto/shash.c:193 shash_digest_unaligned+0xb8/0xe4 crypto/shash.c:201 crypto_shash_digest+0xa4/0xfc     crypto/shash.c:217 crypto_shash_tfm_digest+0xb4/0x150 crypto/shash.c:229 essiv_skcipher_setkey+0x164/0x200     [essiv] crypto_skcipher_setkey+0xb0/0x160 crypto/skcipher.c:612 skcipher_setkey+0x3c/0x50     crypto/algif_skcipher.c:305 alg_setkey+0x114/0x2a0 crypto/af_alg.c:220 alg_setsockopt+0x19c/0x210     crypto/af_alg.c:253 __sys_setsockopt+0x190/0x2e0 net/socket.c:2123 __do_sys_setsockopt net/socket.c:2134     [inline] __se_sys_setsockopt net/socket.c:2131 [inline] __arm64_sys_setsockopt+0x78/0x94 net/socket.c:2131
    __invoke_syscall arch/arm64/kernel/syscall.c:36 [inline] invoke_syscall+0x64/0x100     arch/arm64/kernel/syscall.c:48 el0_svc_common.constprop.0+0x220/0x230 arch/arm64/kernel/syscall.c:155     do_el0_svc+0xb4/0xd4 arch/arm64/kernel/syscall.c:217 el0_svc+0x24/0x3c arch/arm64/kernel/entry-     common.c:353 el0_sync_handler+0x160/0x164 arch/arm64/kernel/entry-common.c:369 el0_sync+0x160/0x180     arch/arm64/kernel/entry.S:683 This error can be reproduced by the following code compiled as ko on a     system with kasan enabled: #include <linux/module.h> #include <linux/crypto.h> #include <crypto/hash.h>     #include <crypto/poly1305.h> char test_data[] = \x00\x01\x02\x03\x04\x05\x06\x07     \x08\x09\x0a\x0b\x0c\x0d\x0e\x0f \x10\x11\x12\x13\x14\x15\x16\x17 \x18\x19\x1a\x1b\x1c\x1d\x1e; int     init(void) { struct crypto_shash *tfm = NULL; char *data = NULL, *out = NULL; tfm =     crypto_alloc_shash(poly1305, 0, 0); data = kmalloc(POLY1305_KEY_SIZE - 1, GFP_KERNEL); out =     kmalloc(POLY1305_DIGEST_SIZE, GFP_KERNEL); memcpy(data, test_data, POLY1305_KEY_SIZE - 1);
    crypto_shash_tfm_digest(tfm, data, POLY1305_KEY_SIZE - 1, out); kfree(data); kfree(out); return 0; } void     deinit(void) { } module_init(init) module_exit(deinit) MODULE_LICENSE(GPL); The root cause of the bug     sits in neon_poly1305_blocks. The logic neon_poly1305_blocks() performed is that if it was called with     both s[] and r[] uninitialized, it will first try to initialize them with the data from the first block     that it believed to be 32 bytes in length. First 16 bytes are used as the key and the next 16 bytes for     s[]. This would lead to the aforementioned read out-of-bound. However, after calling poly1305_init_arch(),     only 16 bytes were deducted from the input and s[] is initialized yet again with the following 16 bytes.
    The second initialization of s[] is certainly redundent which indicates that the first initialization     should be for r[] only. This patch fixes the issue by calling poly1305_init_arm64() instead o
    ---truncated--- (CVE-2022-50231)

  - In the Linux kernel, the following vulnerability has been resolved: bpf: Fix reference state management     for synchronous callbacks Currently, verifier verifies callback functions (sync and async) as if they will     be executed once, (i.e. it explores execution state as if the function was being called once). The next     insn to explore is set to start of subprog and the exit from nested frame is handled using curframe > 0     and prepare_func_exit. In case of async callback it uses a customized variant of push_stack simulating a     kind of branch to set up custom state and execution context for the async callback. While this approach is     simple and works when callback really will be executed only once, it is unsafe for all of our current     helpers which are for_each style, i.e. they execute the callback multiple times. A callback releasing     acquired references of the caller may do so multiple times, but currently verifier sees it as one call     inside the frame, which then returns to caller. Hence, it thinks it released some reference that the cb     e.g. got access through callback_ctx (register filled inside cb from spilled typed register on stack).
    Similarly, it may see that an acquire call is unpaired inside the callback, so the caller will copy the     reference state of callback and then will have to release the register with new ref_obj_ids. But again,     the callback may execute multiple times, but the verifier will only account for acquired references for a     single symbolic execution of the callback, which will cause leaks. Note that for async callback case,     things are different. While currently we have bpf_timer_set_callback which only executes it once, even for     multiple executions it would be safe, as reference state is NULL and check_reference_leak would force     program to release state before BPF_EXIT. The state is also unaffected by analysis for the caller frame.
    Hence async callback is safe. Since we want the reference state to be accessible, e.g. for pointers loaded     from stack through callback_ctx's PTR_TO_STACK, we still have to copy caller's reference_state to     callback's bpf_func_state, but we enforce that whatever references it adds to that reference_state has     been released before it hits BPF_EXIT. This requires introducing a new callback_ref member in the     reference state to distinguish between caller vs callee references. Hence, check_reference_leak now errors     out if it sees we are in callback_fn and we have not released callback_ref refs. Since there can be     multiple nested callbacks, like frame 0 -> cb1 -> cb2 etc. we need to also distinguish between whether     this particular ref belongs to this callback frame or parent, and only error for our own, so we store     state->frameno (which is always non-zero for callbacks). In short, callbacks can read parent     reference_state, but cannot mutate it, to be able to use pointers acquired by the caller. They must only     undo their changes (by releasing their own acquired_refs before BPF_EXIT) on top of caller reference_state     before returning (at which point the caller and callback state will match anyway, so no need to copy it     back to caller). (CVE-2022-50650)

  - In the Linux kernel, the following vulnerability has been resolved: net: stmmac: fix possible memory leak     in stmmac_dvr_probe() The bitmap_free() should be called to free priv->af_xdp_zc_qps when     create_singlethread_workqueue() fails, otherwise there will be a memory leak, so we add the err path     error_wq_init to fix it. (CVE-2022-50663)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - bpf: Fix reference state management for synchronous callbacks Currently, verifier verifies callback     functions (sync and async) as if they will be executed once, (i.e. it explores execution state as if the     function was being called once). The next insn to explore is set to start of subprog and the exit from     nested frame is handled using curframe > 0 and prepare_func_exit. In case of async callback it uses a     customized variant of push_stack simulating a kind of branch to set up custom state and execution context     for the async callback. While this approach is simple and works when callback really will be executed only     once, it is unsafe for all of our current helpers which are for_each style, i.e. they execute the callback     multiple times. A callback releasing acquired references of the caller may do so multiple times, but     currently verifier sees it as one call inside the frame, which then returns to caller. Hence, it thinks it     released some reference that the cb e.g. got access through callback_ctx (register filled inside cb from     spilled typed register on stack). Similarly, it may see that an acquire call is unpaired inside the     callback, so the caller will copy the reference state of callback and then will have to release the     register with new ref_obj_ids. But again, the callback may execute multiple times, but the verifier will     only account for acquired references for a single symbolic execution of the callback, which will cause     leaks. Note that for async callback case, things are different. While currently we have     bpf_timer_set_callback which only executes it once, even for multiple executions it would be safe, as     reference state is NULL and check_reference_leak would force program to release state before BPF_EXIT. The     state is also unaffected by analysis for the caller frame. Hence async callback is safe. Since we want the     reference state to be accessible, e.g. for pointers loaded from stack through callback_ctx's PTR_TO_STACK,     we still have to copy caller's reference_state to callback's bpf_func_state, but we enforce that whatever     references it adds to that reference_state has been released before it hits BPF_EXIT. This requires     introducing a new callback_ref member in the reference state to distinguish between caller vs callee     references. Hence, check_reference_leak now errors out if it sees we are in callback_fn and we have not     released callback_ref refs. Since there can be multiple nested callbacks, like frame 0 -> cb1 -> cb2 etc.
    we need to also distinguish between whether this particular ref belongs to this callback frame or parent,     and only error for our own, so we store state->frameno (which is always non-zero for callbacks). In short,     callbacks can read parent reference_state, but cannot mutate it, to be able to use pointers acquired by     the caller. They must only undo their changes (by releasing their own acquired_refs before BPF_EXIT) on     top of caller reference_state before returning (at which point the caller and callback state will match     anyway, so no need to copy it back to caller). (CVE-2022-50650)

Note that Nessus relies on the presence of the package as reported by the vendor.

The version of kernel installed on the remote host is prior to 5.15.75-48.135. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2KERNEL-5.15-2025-090 advisory.

    A vulnerability, which was classified as problematic, has been found in Linux Kernel. This issue affects     the function nilfs_attach_log_writer of the file fs/nilfs2/segment.c of the component BPF. The     manipulation leads to memory leak. The attack may be initiated remotely. It is recommended to apply a     patch to fix this issue. The identifier VDB-211961 was assigned to this vulnerability. (CVE-2022-3646)

    drivers/scsi/stex.c in the Linux kernel through 5.19.9 allows local users to obtain sensitive information     from kernel memory because stex_queuecommand_lck lacks a memset for the PASSTHRU_CMD case.
    (CVE-2022-40768)

    The Linux kernel NFSD implementation prior to versions 5.19.17 and 6.0.2 are vulnerable to buffer     overflow. NFSD tracks the number of pages held by each NFSD thread by combining the receive and send     buffers of a remote procedure call (RPC) into a single array of pages. A client can force the send buffer     to shrink by sending an RPC message over TCP with garbage data added at the end of the message. The RPC     message with garbage data is still correctly formed according to the specification and is passed forward     to handlers. Vulnerable code in NFSD is not expecting the oversized request and writes beyond the     allocated buffer space. CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H (CVE-2022-43945)

    In the Linux kernel, the following vulnerability has been resolved:

    NFSD: Protect against send buffer overflow in NFSv2 READDIR (CVE-2022-50235)

    In the Linux kernel, the following vulnerability has been resolved:

    NFSD: fix use-after-free on source server when doing inter-server copy (CVE-2022-50241)

    In the Linux kernel, the following vulnerability has been resolved:

    sctp: handle the error returned from sctp_auth_asoc_init_active_key (CVE-2022-50243)

    In the Linux kernel, the following vulnerability has been resolved:

    xen/gntdev: Prevent leaking grants (CVE-2022-50257)

    In the Linux kernel, the following vulnerability has been resolved:

    vhost/vsock: Use kvmalloc/kvfree for larger packets. (CVE-2022-50271)

    In the Linux kernel, the following vulnerability has been resolved:

    md: Replace snprintf with scnprintf (CVE-2022-50299)

    In the Linux kernel, the following vulnerability has been resolved:

    nbd: Fix hung when signal interrupts nbd_start_device_ioctl() (CVE-2022-50314)

    In the Linux kernel, the following vulnerability has been resolved:

    jbd2: fix potential use-after-free in jbd2_fc_wait_bufs (CVE-2022-50328)

    In the Linux kernel, the following vulnerability has been resolved:

    ext4: fix null-ptr-deref in ext4_write_info (CVE-2022-50344)

    In the Linux kernel, the following vulnerability has been resolved:

    NFSD: Protect against send buffer overflow in NFSv3 READ (CVE-2022-50345)

    In the Linux kernel, the following vulnerability has been resolved:

    nfsd: Fix a memory leak in an error handling path (CVE-2022-50348)

    In the Linux kernel, the following vulnerability has been resolved:

    btrfs: fix race between quota enable and quota rescan ioctl (CVE-2022-50379)

    In the Linux kernel, the following vulnerability has been resolved:

    net/ieee802154: reject zero-sized raw_sendmsg() (CVE-2022-50397)

    In the Linux kernel, the following vulnerability has been resolved:

    net: If sock is dead don't access sock's sk_wq in sk_stream_wait_memory (CVE-2022-50409)

    In the Linux kernel, the following vulnerability has been resolved:

    NFSD: Protect against send buffer overflow in NFSv2 READ (CVE-2022-50410)

    In the Linux kernel, the following vulnerability has been resolved:

    scsi: libsas: Fix use-after-free bug in smp_execute_task_sg() (CVE-2022-50422)

    In the Linux kernel, the following vulnerability has been resolved:

    ext4: avoid crash when inline data creation follows DIO write (CVE-2022-50435)

    In the Linux kernel, the following vulnerability has been resolved:

    xfrm: Reinject transport-mode packets through workqueue (CVE-2022-50445)

    In the Linux kernel, the following vulnerability has been resolved:

    xen/gntdev: Accommodate VMA splitting (CVE-2022-50471)

    In the Linux kernel, the following vulnerability has been resolved:

    drm/mipi-dsi: Detach devices when removing the host (CVE-2022-50489)

    In the Linux kernel, the following vulnerability has been resolved:

    bpf: Propagate error from htab_lock_bucket() to userspace (CVE-2022-50490)

    In the Linux kernel, the following vulnerability has been resolved:

    ext4: fix potential memory leak in ext4_fc_record_regions() (CVE-2022-50512)

    In the Linux kernel, the following vulnerability has been resolved:

    usb: host: xhci: Fix potential memory leak in xhci_alloc_stream_info() (CVE-2022-50544)

    In the Linux kernel, the following vulnerability has been resolved:

    xfrm: Update ipcomp_scratches with NULL when freed (CVE-2022-50569)

    In the Linux kernel, the following vulnerability has been resolved:

    arm64: ftrace: fix module PLTs with mcount (CVE-2022-50579)

    In the Linux kernel, the following vulnerability has been resolved:

    blk-throttle: prevent overflow while calculating wait time (CVE-2022-50580)

    In the Linux kernel, the following vulnerability has been resolved:

    ext4: fix potential memory leak in ext4_fc_record_modified_inode() (CVE-2022-50622)

    In the Linux kernel, the following vulnerability has been resolved:

    mm: hugetlb: fix UAF in hugetlb_handle_userfault (CVE-2022-50630)

    In the Linux kernel, the following vulnerability has been resolved:

    io-wq: Fix memory leak in worker creation (CVE-2022-50639)

    In the Linux kernel, the following vulnerability has been resolved:

    bpf: Fix reference state management for synchronous callbacks (CVE-2022-50650)

    In the Linux kernel, the following vulnerability has been resolved:

    RDMA/siw: Fix QP destroy to wait for all references dropped. (CVE-2022-50666)

    In the Linux kernel, the following vulnerability has been resolved:

    net: rds: don't hold sock lock when cancelling work from rds_tcp_reset_callbacks() (CVE-2022-50676)

    In the Linux kernel, the following vulnerability has been resolved:

    net/ieee802154: don't warn zero-sized raw_sendmsg() (CVE-2022-50706)

    In the Linux kernel, the following vulnerability has been resolved:

    crypto: akcipher - default implementation for setting a private key (CVE-2022-50731)

    In the Linux kernel, the following vulnerability has been resolved:

    md/raid5: Remove unnecessary bio_put() in raid5_read_one_chunk() (CVE-2022-50752)

    In the Linux kernel, the following vulnerability has been resolved:

    btrfs: set generation before calling btrfs_clean_tree_block in btrfs_init_new_buffer (CVE-2022-50766)

    In the Linux kernel, the following vulnerability has been resolved:

    jbd2: add miss release buffer head in fc_do_one_pass() (CVE-2022-50835)

    In the Linux kernel, the following vulnerability has been resolved:

    jbd2: fix potential buffer head reference count leak (CVE-2022-50839)

    In the Linux kernel, the following vulnerability has been resolved:

    cifs: Fix the error length of VALIDATE_NEGOTIATE_INFO message (CVE-2022-50859)

    In the Linux kernel, the following vulnerability has been resolved:

    drm: Prevent drm_copy_field() to attempt copying a NULL pointer (CVE-2022-50884)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

ID	Name	Product	Family	Type	Severity
352031	AlmaLinux 9.2 [TuxCare] Security Update: bpftool / kernel / kernel-64k / kernel-64k-core / kernel-64k-debug / etc Multiple Vulnerabilities (ALMALINUX9.2:CLSA-2026:1786761805)	Nessus	Alma Linux Local Security Checks	Local	critical
278044	Linux Distros Unpatched Vulnerability : CVE-2022-50650	Nessus	Misc.	Local	high
266163	Amazon Linux 2 : kernel, --advisory ALAS2KERNEL-5.15-2025-090 (ALASKERNEL-5.15-2025-090)	Nessus	Amazon Linux Local Security Checks	Local	high

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