In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_taprio: fix possible use-after-free syzbot reported a nasty crash [1] in net_tx_action() which made little sense until we got a repro. This repro installs a taprio qdisc, but providing an invalid TCA_RATE attribute. qdisc_create() has to destroy the just initialized taprio qdisc, and taprio_destroy() is called. However, the hrtimer used by taprio had already fired, therefore advance_sched() called __netif_schedule(). Then net_tx_action was trying to use a destroyed qdisc. We can not undo the __netif_schedule(), so we must wait until one cpu serviced the qdisc before we can proceed. Many thanks to Alexander Potapenko for his help. [1] BUG: KMSAN: uninit-value in queued_spin_trylock include/asm-generic/qspinlock.h:94 [inline] BUG: KMSAN: uninit-value in do_raw_spin_trylock include/linux/spinlock.h:191 [inline] BUG: KMSAN: uninit-value in __raw_spin_trylock include/linux/spinlock_api_smp.h:89 [inline] BUG: KMSAN: uninit-value in _raw_spin_trylock+0x92/0xa0 kernel/locking/spinlock.c:138 queued_spin_trylock include/asm-generic/qspinlock.h:94 [inline] do_raw_spin_trylock include/linux/spinlock.h:191 [inline] __raw_spin_trylock include/linux/spinlock_api_smp.h:89 [inline] _raw_spin_trylock+0x92/0xa0 kernel/locking/spinlock.c:138 spin_trylock include/linux/spinlock.h:359 [inline] qdisc_run_begin include/net/sch_generic.h:187 [inline] qdisc_run+0xee/0x540 include/net/pkt_sched.h:125 net_tx_action+0x77c/0x9a0 net/core/dev.c:5086 __do_softirq+0x1cc/0x7fb kernel/softirq.c:571 run_ksoftirqd+0x2c/0x50 kernel/softirq.c:934 smpboot_thread_fn+0x554/0x9f0 kernel/smpboot.c:164 kthread+0x31b/0x430 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 Uninit was created at: slab_post_alloc_hook mm/slab.h:732 [inline] slab_alloc_node mm/slub.c:3258 [inline] __kmalloc_node_track_caller+0x814/0x1250 mm/slub.c:4970 kmalloc_reserve net/core/skbuff.c:358 [inline] __alloc_skb+0x346/0xcf0 net/core/skbuff.c:430 alloc_skb include/linux/skbuff.h:1257 [inline] nlmsg_new include/net/netlink.h:953 [inline] netlink_ack+0x5f3/0x12b0 net/netlink/af_netlink.c:2436 netlink_rcv_skb+0x55d/0x6c0 net/netlink/af_netlink.c:2507 rtnetlink_rcv+0x30/0x40 net/core/rtnetlink.c:6108 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0xf3b/0x1270 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x1288/0x1440 net/netlink/af_netlink.c:1921 sock_sendmsg_nosec net/socket.c:714 [inline] sock_sendmsg net/socket.c:734 [inline] ____sys_sendmsg+0xabc/0xe90 net/socket.c:2482 ___sys_sendmsg+0x2a1/0x3f0 net/socket.c:2536 __sys_sendmsg net/socket.c:2565 [inline] __do_sys_sendmsg net/socket.c:2574 [inline] __se_sys_sendmsg net/socket.c:2572 [inline] __x64_sys_sendmsg+0x367/0x540 net/socket.c:2572 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd CPU: 0 PID: 13 Comm: ksoftirqd/0 Not tainted 6.0.0-rc2-syzkaller-47461-gac3859c02d7f #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022

The version of kernel installed on the remote host is prior to 5.10.167-147.601. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2KERNEL-5.10-2025-089 advisory.

    A flaw was found in the Linux kernel's Layer 2 Tunneling Protocol (L2TP). A missing lock when clearing     sk_user_data can lead to a race condition and NULL pointer dereference. A local user could use this flaw     to potentially crash the system causing a denial of service. (CVE-2022-4129)

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

    dmaengine: Fix double increment of client_count in dma_chan_get() (CVE-2022-49753)

    A memory corruption flaw was found in the Linux kernel's human interface device (HID) subsystem in how a     user inserts a malicious USB device. This flaw allows a local user to crash or potentially escalate their     privileges on the system. (CVE-2023-1073)

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

    net: fix UaF in netns ops registration error path (CVE-2023-52999)

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

    net/sched: sch_taprio: fix possible use-after-free (CVE-2023-53021)

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.

The version of kernel installed on the remote host is prior to 5.15.93-55.139. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2KERNEL-5.15-2024-037 advisory.

    A flaw was found in the Linux kernel's Layer 2 Tunneling Protocol (L2TP). A missing lock when clearing     sk_user_data can lead to a race condition and NULL pointer dereference. A local user could use this flaw     to potentially crash the system causing a denial of service. (CVE-2022-4129)

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

    dmaengine: Fix double increment of client_count in dma_chan_get() (CVE-2022-49753)

    A flaw was found in the Linux kernel, where unauthorized access to the execution of the setuid file with     capabilities was found in the Linux kernel's OverlayFS subsystem in how a user copies a capable file from     a nosuid mount into another mount. This uid mapping bug allows a local user to escalate their privileges     on the system. (CVE-2023-0386)

    A memory corruption flaw was found in the Linux kernel's human interface device (HID) subsystem in how a     user inserts a malicious USB device. This flaw allows a local user to crash or potentially escalate their     privileges on the system. (CVE-2023-1073)

    A use-after-free flaw was found in nfsd4_ssc_setup_dul in fs/nfsd/nfs4proc.c in the NFS filesystem in the     Linux Kernel. This issue could allow a local attacker to crash the system or it may lead to a kernel     information leak problem. (CVE-2023-1652)

    In the Linux kernel 6.0.8, there is a use-after-free in inode_cgwb_move_to_attached in fs/fs-writeback.c,     related to __list_del_entry_valid. (CVE-2023-26605)

    A flaw was found in the Framebuffer Console (fbcon) in the Linux Kernel. When providing a font->width and     font->height greater than 32 to the fbcon_set_font, since there are no checks in place, a shift-out-of-     bounds occurs, leading to undefined behavior and possible denial of service. (CVE-2023-3161)

    A use-after-free flaw was found in vcs_read in drivers/tty/vt/vc_screen.c in vc_screen in the Linux     Kernel. In this flaw an attacker with local user access may lead to a system crash or a leak of internal     kernel information. (CVE-2023-3567)

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

    drm/i915: Fix potential bit_17 double-free (CVE-2023-52930)

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

    vc_screen: move load of struct vc_data pointer in vcs_read() to avoid UAF (CVE-2023-52973)

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

    block, bfq: fix uaf for bfqq in bic_set_bfqq() (CVE-2023-52983)

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

    net: fix UaF in netns ops registration error path (CVE-2023-52999)

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

    net/sched: sch_taprio: fix possible use-after-free (CVE-2023-53021)

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

    NFSD: fix use-after-free in nfsd4_ssc_setup_dul() (CVE-2023-53025)

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.

The version of kernel installed on the remote host is prior to 5.4.231-137.341. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2KERNEL-5.4-2023-042 advisory.

    A flaw was found in the Linux kernel's Layer 2 Tunneling Protocol (L2TP). A missing lock when clearing     sk_user_data can lead to a race condition and NULL pointer dereference. A local user could use this flaw     to potentially crash the system causing a denial of service. (CVE-2022-4129)

    In the Linux kernel before 6.1.6, a NULL pointer dereference bug in the traffic control subsystem allows     an unprivileged user to trigger a denial of service (system crash) via a crafted traffic control     configuration that is set up with tc qdisc and tc class commands. This affects qdisc_graft in     net/sched/sch_api.c. (CVE-2022-47929)

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

    udf: Fix preallocation discarding at indirect extent boundary (CVE-2022-48946)

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

    igb: Initialize mailbox message for VF reset (CVE-2022-48949)

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

    dmaengine: Fix double increment of client_count in dma_chan_get() (CVE-2022-49753)

    The Linux kernel does not correctly mitigate SMT attacks, as discovered through a strange pattern in the     kernel API using STIBP as a mitigation, leaving the process exposed for a short period of time after a     syscall. The kernel also does not issue an IBPB immediately during the syscall. (CVE-2023-0045)

    A NULL pointer dereference flaw was found in rawv6_push_pending_frames in net/ipv6/raw.c in the network     subcomponent in the Linux kernel. This flaw causes the system to crash. (CVE-2023-0394)

    Detected a few exploitable gadgets that could leak secret memory through a side-channel such as MDS as     well as insufficient hardening of the usercopy functions against spectre-v1. (CVE-2023-0459)

    There is a use-after-free vulnerability in the Linux Kernel which can be exploited to achieve local     privilege escalation. To reach the vulnerability kernel configuration flag CONFIG_TLS or     CONFIG_XFRM_ESPINTCP has to be configured, but the operation does not require any privilege.

    There is a use-after-free bug of icsk_ulp_data of a struct inet_connection_sock.

    When CONFIG_TLS is enabled, user can install a tls context (struct tls_context) on a connected tcp socket.
    The context is not cleared if this socket is disconnected and reused as a listener. If a new socket is     created from the listener, the context is inherited and vulnerable.

    The setsockopt TCP_ULP operation does not require any privilege.

    We recommend upgrading past commit 2c02d41d71f90a5168391b6a5f2954112ba2307c (CVE-2023-0461)

    A memory corruption flaw was found in the Linux kernel's human interface device (HID) subsystem in how a     user inserts a malicious USB device. This flaw allows a local user to crash or potentially escalate their     privileges on the system. (CVE-2023-1073)

    cbq_classify in net/sched/sch_cbq.c in the Linux kernel through 6.1.4 allows attackers to cause a denial     of service (slab-out-of-bounds read) because of type confusion (non-negative numbers can sometimes     indicate a TC_ACT_SHOT condition rather than valid classification results). (CVE-2023-23454)

    atm_tc_enqueue in net/sched/sch_atm.c in the Linux kernel through 6.1.4 allows attackers to cause a denial     of service because of type confusion (non-negative numbers can sometimes indicate a TC_ACT_SHOT condition     rather than valid classification results). (CVE-2023-23455)

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

    net/sched: act_mpls: Fix warning during failed attribute validation (CVE-2023-52906)

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

    net: fix UaF in netns ops registration error path (CVE-2023-52999)

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

    net/sched: sch_taprio: fix possible use-after-free (CVE-2023-53021)

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	Severity
234965	Amazon Linux 2 : kernel (ALASKERNEL-5.10-2025-089)	Nessus	Amazon Linux Local Security Checks	medium
190056	Amazon Linux 2 : kernel (ALASKERNEL-5.15-2024-037)	Nessus	Amazon Linux Local Security Checks	high
171848	Amazon Linux 2 : kernel (ALASKERNEL-5.4-2023-042)	Nessus	Amazon Linux Local Security Checks	high

Detections

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CVE-2023-53021

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Tenable Plugins

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