In the Linux kernel, the following vulnerability has been resolved: xfs: check for deleted cursors when revalidating two btrees The free space and inode btree repair functions will rebuild both btrees at the same time, after which it needs to evaluate both btrees to confirm that the corruptions are gone. However, Jiaming Zhang ran syzbot and produced a crash in the second xchk_allocbt call. His root-cause analysis is as follows (with minor corrections): In xrep_revalidate_allocbt(), xchk_allocbt() is called twice (first for BNOBT, second for CNTBT). The cause of this issue is that the first call nullified the cursor required by the second call. Let's first enter xrep_revalidate_allocbt() via following call chain: xfs_file_ioctl() -> xfs_ioc_scrubv_metadata() -> xfs_scrub_metadata() -> `sc->ops->repair_eval(sc)` -> xrep_revalidate_allocbt() xchk_allocbt() is called twice in this function. In the first call: /* Note that sc->sm->sm_type is XFS_SCRUB_TYPE_BNOPT now */ xchk_allocbt() -> xchk_btree() -> `bs->scrub_rec(bs, recp)` -> xchk_allocbt_rec() -> xchk_allocbt_xref() -> xchk_allocbt_xref_other() since sm_type is XFS_SCRUB_TYPE_BNOBT, pur is set to &sc->sa.cnt_cur. Kernel called xfs_alloc_get_rec() and returned -EFSCORRUPTED. Call chain: xfs_alloc_get_rec() -> xfs_btree_get_rec() -> xfs_btree_check_block() -> (XFS_IS_CORRUPT || XFS_TEST_ERROR), the former is false and the latter is true, return -EFSCORRUPTED. This should be caused by ioctl$XFS_IOC_ERROR_INJECTION I guess. Back to xchk_allocbt_xref_other(), after receiving -EFSCORRUPTED from xfs_alloc_get_rec(), kernel called xchk_should_check_xref(). In this function, *curpp (points to sc->sa.cnt_cur) is nullified. Back to xrep_revalidate_allocbt(), since sc->sa.cnt_cur has been nullified, it then triggered null-ptr-deref via xchk_allocbt() (second call) -> xchk_btree(). So. The bnobt revalidation failed on a cross-reference attempt, so we deleted the cntbt cursor, and then crashed when we tried to revalidate the cntbt. Therefore, check for a null cntbt cursor before that revalidation, and mark the repair incomplete. Also we can ignore the second tree entirely if the first tree was rebuilt but is already corrupt. Apply the same fix to xrep_revalidate_iallocbt because it has the same problem.

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-1543 advisory.

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

    fs/xattr: missing fdput() in fremovexattr error path (CVE-2024-14027)

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

    audit: add fchmodat2() to change attributes class (CVE-2025-71239)

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

    fs: ntfs3: fix infinite loop in attr_load_runs_range on inconsistent metadata (CVE-2025-71265)

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

    fs: ntfs3: check return value of indx_find to avoid infinite loop (CVE-2025-71266)

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

    fs: ntfs3: fix infinite loop triggered by zero-sized ATTR_LIST (CVE-2025-71267)

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

    btrfs: do not strictly require dirty metadata threshold for metadata writepages (CVE-2026-23157)

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

    netfilter: nf_tables: fix use-after-free in nf_tables_addchain() (CVE-2026-23231)

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

    espintcp: Fix race condition in espintcp_close() (CVE-2026-23239)

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

    tls: Fix race condition in tls_sw_cancel_work_tx() (CVE-2026-23240)

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

    RDMA/umad: Reject negative data_len in ib_umad_write (CVE-2026-23243)

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

    nvme: fix memory allocation in nvme_pr_read_keys() (CVE-2026-23244)

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

    xfs: check for deleted cursors when revalidating two btrees (CVE-2026-23249)

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

    net/sched: Only allow act_ct to bind to clsact/ingress qdiscs and shared blocks (CVE-2026-23270)

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

    perf: Fix __perf_event_overflow() vs perf_remove_from_context() race (CVE-2026-23271)

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

    macvlan: observe an RCU grace period in macvlan_common_newlink() error path (CVE-2026-23273)

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

    drbd: fix null-pointer dereference on local read error (CVE-2026-23285)

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

    scsi: target: Fix recursive locking in __configfs_open_file() (CVE-2026-23292)

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

    net: vxlan: fix nd_tbl NULL dereference when IPv6 is disabled (CVE-2026-23293)

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

    scsi: core: Fix refcount leak for tagset_refcnt (CVE-2026-23296)

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

    nfsd: Fix cred ref leak in nfsd_nl_threads_set_doit(). (CVE-2026-23297)

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

    net: ipv6: fix panic when IPv4 route references loopback IPv6 nexthop (CVE-2026-23300)

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

    smb: client: Don't log plaintext credentials in cifs_set_cifscreds (CVE-2026-23303)

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

    ipv6: fix NULL pointer deref in ip6_rt_get_dev_rcu() (CVE-2026-23304)

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

    bpf/bonding: reject vlan+srcmac xmit_hash_policy change when XDP is loaded (CVE-2026-23310)

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

    i40e: Fix preempt count leak in napi poll tracepoint (CVE-2026-23313)

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

    net: ipv4: fix ARM64 alignment fault in multipath hash seed (CVE-2026-23316)

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

    drm/vmwgfx: Return the correct value in vmw_translate_ptr functions (CVE-2026-23317)

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

    bpf: Fix a UAF issue in bpf_trampoline_link_cgroup_shim (CVE-2026-23319)

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

    RDMA/irdma: Fix kernel stack leak in irdma_create_user_ah() (CVE-2026-23335)

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

    net: sched: avoid qdisc_reset_all_tx_gt() vs dequeue race for lockless qdiscs (CVE-2026-23340)

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

    xdp: produce a warning when calculated tailroom is negative (CVE-2026-23343)

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

    netfilter: nft_set_pipapo: split gc into unlink and reclaim phase (CVE-2026-23351)

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

    x86/efi: defer freeing of boot services memory (CVE-2026-23352)

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

    x86/fred: Correct speculative safety in fred_extint() (CVE-2026-23354)

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

    drbd: fix LOGIC BUG in drbd_al_begin_io_nonblock() (CVE-2026-23356)

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

    bpf: Fix stack-out-of-bounds write in devmap (CVE-2026-23359)

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

    nvme: fix admin queue leak on controller reset (CVE-2026-23360)

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

    PCI: dwc: ep: Flush MSI-X write before unmapping its ATU entry (CVE-2026-23361)

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

    can: bcm: fix locking for bcm_op runtime updates (CVE-2026-23362)

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

    i2c: i801: Revert i2c: i801: replace acpi_lock with I2C bus lock (CVE-2026-23369)

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

    net/sched: ets: fix divide by zero in the offload path (CVE-2026-23379)

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

    tracing: Fix WARN_ON in tracing_buffers_mmap_close (CVE-2026-23380)

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

    net: bridge: fix nd_tbl NULL dereference when IPv6 is disabled (CVE-2026-23381)

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

    bpf, arm64: Force 8-byte alignment for JIT buffer to prevent atomic tearing (CVE-2026-23383)

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

    Squashfs: check metadata block offset is within range (CVE-2026-23388)

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

    net/rds: Fix circular locking dependency in rds_tcp_tune (CVE-2026-23419)

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.

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-1515 advisory.

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

    audit: add fchmodat2() to change attributes class (CVE-2025-71239)

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

    fs: ntfs3: fix infinite loop in attr_load_runs_range on inconsistent metadata (CVE-2025-71265)

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

    fs: ntfs3: check return value of indx_find to avoid infinite loop (CVE-2025-71266)

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

    fs: ntfs3: fix infinite loop triggered by zero-sized ATTR_LIST (CVE-2025-71267)

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

    espintcp: Fix race condition in espintcp_close() (CVE-2026-23239)

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

    tls: Fix race condition in tls_sw_cancel_work_tx() (CVE-2026-23240)

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

    audit: add missing syscalls to read class (CVE-2026-23241)

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

    xfs: check for deleted cursors when revalidating two btrees (CVE-2026-23249)

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

  - xfs: check for deleted cursors when revalidating two btrees The free space and inode btree repair     functions will rebuild both btrees at the same time, after which it needs to evaluate both btrees to     confirm that the corruptions are gone. However, Jiaming Zhang ran syzbot and produced a crash in the     second xchk_allocbt call. His root-cause analysis is as follows (with minor corrections): In     xrep_revalidate_allocbt(), xchk_allocbt() is called twice (first for BNOBT, second for CNTBT). The cause     of this issue is that the first call nullified the cursor required by the second call. Let's first enter     xrep_revalidate_allocbt() via following call chain: xfs_file_ioctl() -> xfs_ioc_scrubv_metadata() ->     xfs_scrub_metadata() -> `sc->ops->repair_eval(sc)` -> xrep_revalidate_allocbt() xchk_allocbt() is called     twice in this function. In the first call: /* Note that sc->sm->sm_type is XFS_SCRUB_TYPE_BNOPT now */     xchk_allocbt() -> xchk_btree() -> `bs->scrub_rec(bs, recp)` -> xchk_allocbt_rec() -> xchk_allocbt_xref()
    -> xchk_allocbt_xref_other() since sm_type is XFS_SCRUB_TYPE_BNOBT, pur is set to &sc->sa.cnt_cur. Kernel     called xfs_alloc_get_rec() and returned -EFSCORRUPTED. Call chain: xfs_alloc_get_rec() ->     xfs_btree_get_rec() -> xfs_btree_check_block() -> (XFS_IS_CORRUPT || XFS_TEST_ERROR), the former is false     and the latter is true, return -EFSCORRUPTED. This should be caused by ioctl$XFS_IOC_ERROR_INJECTION I     guess. Back to xchk_allocbt_xref_other(), after receiving -EFSCORRUPTED from xfs_alloc_get_rec(), kernel     called xchk_should_check_xref(). In this function, *curpp (points to sc->sa.cnt_cur) is nullified. Back to     xrep_revalidate_allocbt(), since sc->sa.cnt_cur has been nullified, it then triggered null-ptr-deref via     xchk_allocbt() (second call) -> xchk_btree(). So. The bnobt revalidation failed on a cross-reference     attempt, so we deleted the cntbt cursor, and then crashed when we tried to revalidate the cntbt.
    Therefore, check for a null cntbt cursor before that revalidation, and mark the repair incomplete. Also we     can ignore the second tree entirely if the first tree was rebuilt but is already corrupt. Apply the same     fix to xrep_revalidate_iallocbt because it has the same problem. (CVE-2026-23249)

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

ID	Name	Product	Family	Severity
305231	Amazon Linux 2023 : bpftool6.12, kernel6.12, kernel6.12-devel (ALAS2023-2026-1543)	Nessus	Amazon Linux Local Security Checks	high
304620	Amazon Linux 2023 : bpftool6.18, kernel6.18, kernel6.18-devel (ALAS2023-2026-1515)	Nessus	Amazon Linux Local Security Checks	critical
302930	Linux Distros Unpatched Vulnerability : CVE-2026-23249	Nessus	Misc.	medium

Detections

Analytics

CVE-2026-23249

medium

Tenable Plugins

high

critical

medium