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TI-2026-24265 Aliases CVE-2026-31709GHSA-8hp2-qmc6-f97h

smb: client: validate the whole DACL before rewriting it in cifsacl

Priority MEDIUM 40CWE-125Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Required
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
High · High · High
Fix status
Partial Red Hat: 32 fixed, 1 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.

Summary

In the Linux kernel, the following vulnerability has been resolved: smb: client: validate the whole DACL before rewriting it in cifsacl build_sec_desc() and id_mode_to_cifs_acl() derive a DACL pointer from a server-supplied dacloffset and then use the incoming ACL to rebuild the chmod/chown security descriptor. The original fix only checked that the struct smb_acl header fits before reading dacl_ptr->size or dacl_ptr->num_aces. That avoids the immediate header-field OOB read, but the rewrite helpers still walk ACEs based on pdacl->num_aces with no structural validation of the incoming DACL body. A malicious server can return a truncated DACL that still contains a header, claims one or more ACEs, and then drive replace_sids_and_copy_aces() or set_chmod_dacl() past the validated extent while they compare or copy attacker-controlled ACEs. Factor the DACL structural checks into validate_dacl(), extend them to validate each ACE against the DACL bounds, and use the shared validator before the chmod/chown rebuild paths. parse_dacl() reuses the same validator so the read-side parser and write-side rewrite paths agree on what constitutes a well-formed incoming DACL.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00345 28th percentileScored 2026-11-07
Fix Partial Linux (Linux): 5.15.210, 6.1.176, 6.6.140 +4Red Hat: 9 advisoriesRed Hat: 32 fixed, 1 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux5.12 and later5.15.210, 6.1.176, 6.6.140, 6.12.86, 6.18.35, 7.0.2, 7.1Patch availableCNA
  • Linux VendorLinux Affected 5.12 and later Fixed in 5.15.210, 6.1.176, 6.6.140, 6.12.86, 6.18.35, 7.0.2, 7.1 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*5.12 to before 7.0.2VulnerableLinux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 5.12 to before 7.0.2 Vulnerable ·Linux

Remediation

  • Fix · CNA Linux (Linux) Fixed in 5.15.210, 6.1.176, 6.6.140, 6.12.86, 6.18.35, 7.0.2, 7.1

Red Hat 9 advisories

  • RHSA-2026:24343 Released 2026-06-08 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux AppStream EUS (v. 10.0) kernel-64k-debug-devel-6.12.0-55.77.1.el10_0, kernel-64k-debug-devel-matched-6.12.0-55.77.1.el10_0, kernel-64k-devel-6.12.0-55.77.1.el10_0 +12
    • Red Hat Enterprise Linux BaseOS EUS (v. 10.0) kernel-6.12.0-55.77.1.el10_0, kernel-64k-6.12.0-55.77.1.el10_0, kernel-64k-core-6.12.0-55.77.1.el10_0 +28
    • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) kernel-tools-libs-devel-6.12.0-55.77.1.el10_0, libperf-6.12.0-55.77.1.el10_0
    • Red Hat Enterprise Linux Real Time EUS (v. 10.0) kernel-rt-6.12.0-55.77.1.el10_0, kernel-rt-64k-6.12.0-55.77.1.el10_0, kernel-rt-64k-core-6.12.0-55.77.1.el10_0 +21
    • Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0) kernel-rt-6.12.0-55.77.1.el10_0, kernel-rt-core-6.12.0-55.77.1.el10_0, kernel-rt-debug-6.12.0-55.77.1.el10_0 +11
  • RHSA-2026:23329 Released 2026-06-04 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux AppStream (v. 10) kernel-64k-debug-devel-6.12.0-211.20.1.el10_2, kernel-64k-debug-devel-matched-6.12.0-211.20.1.el10_2, kernel-64k-devel-6.12.0-211.20.1.el10_2 +12
    • Red Hat Enterprise Linux BaseOS (v. 10) kernel-6.12.0-211.20.1.el10_2, kernel-64k-6.12.0-211.20.1.el10_2, kernel-64k-core-6.12.0-211.20.1.el10_2 +29
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) kernel-tools-libs-devel-6.12.0-211.20.1.el10_2, libperf-6.12.0-211.20.1.el10_2
    • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt-6.12.0-211.20.1.el10_2, kernel-rt-64k-6.12.0-211.20.1.el10_2, kernel-rt-64k-core-6.12.0-211.20.1.el10_2 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt-6.12.0-211.20.1.el10_2, kernel-rt-core-6.12.0-211.20.1.el10_2, kernel-rt-debug-6.12.0-211.20.1.el10_2 +9
  • RHSA-2026:23224 Released 2026-06-04 · Red Hat rating Important
    kernel security update
    • Red Hat CodeReady Linux Builder EUS (v.9.6) kernel-tools-libs-devel-5.14.0-570.119.1.el9_6, libperf-5.14.0-570.119.1.el9_6
    • Red Hat Enterprise Linux AppStream EUS (v.9.6) kernel-64k-debug-devel-5.14.0-570.119.1.el9_6, kernel-64k-debug-devel-matched-5.14.0-570.119.1.el9_6, kernel-64k-devel-5.14.0-570.119.1.el9_6 +12
    • Red Hat Enterprise Linux BaseOS EUS (v.9.6) kernel-5.14.0-570.119.1.el9_6, kernel-64k-5.14.0-570.119.1.el9_6, kernel-64k-core-5.14.0-570.119.1.el9_6 +28
    • Red Hat Enterprise Linux Real Time EUS (v.9.6) kernel-rt-5.14.0-570.119.1.el9_6, kernel-rt-64k-5.14.0-570.119.1.el9_6, kernel-rt-64k-core-5.14.0-570.119.1.el9_6 +21
    • Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6) kernel-rt-5.14.0-570.119.1.el9_6, kernel-rt-core-5.14.0-570.119.1.el9_6, kernel-rt-debug-5.14.0-570.119.1.el9_6 +11
Show 6 more Red Hat advisories
  • RHSA-2026:23237 Released 2026-06-04 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux AppStream E4S (v.9.4) kernel-64k-debug-devel-5.14.0-427.129.1.el9_4, kernel-64k-debug-devel-matched-5.14.0-427.129.1.el9_4, kernel-64k-devel-5.14.0-427.129.1.el9_4 +11
    • Red Hat Enterprise Linux BaseOS E4S (v.9.4) bpftool-7.3.0-427.129.1.el9_4, kernel-5.14.0-427.129.1.el9_4, kernel-64k-5.14.0-427.129.1.el9_4 +29
    • Red Hat Enterprise Linux Real Time E4S (v.9.4) kernel-rt-5.14.0-427.129.1.el9_4, kernel-rt-core-5.14.0-427.129.1.el9_4, kernel-rt-debug-5.14.0-427.129.1.el9_4 +9
    • Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4) kernel-rt-5.14.0-427.129.1.el9_4, kernel-rt-core-5.14.0-427.129.1.el9_4, kernel-rt-debug-5.14.0-427.129.1.el9_4 +11
  • RHSA-2026:22940 Released 2026-06-03 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux AppStream E4S (v.9.2) kernel-64k-debug-devel-5.14.0-284.174.1.el9_2, kernel-64k-debug-devel-matched-5.14.0-284.174.1.el9_2, kernel-64k-devel-5.14.0-284.174.1.el9_2 +10
    • Red Hat Enterprise Linux BaseOS E4S (v.9.2) bpftool-7.0.0-284.174.1.el9_2, kernel-5.14.0-284.174.1.el9_2, kernel-64k-5.14.0-284.174.1.el9_2 +29
  • RHSA-2026:22900 Released 2026-06-03 · Red Hat rating Important
    kernel-rt security update
    • Red Hat Enterprise Linux Real Time E4S (v.9.2) kernel-rt-5.14.0-284.174.1.rt14.459.el9_2, kernel-rt-core-5.14.0-284.174.1.rt14.459.el9_2, kernel-rt-debug-5.14.0-284.174.1.rt14.459.el9_2 +9
    • Red Hat Enterprise Linux Real Time for NFV E4S (v.9.2) kernel-rt-5.14.0-284.174.1.rt14.459.el9_2, kernel-rt-core-5.14.0-284.174.1.rt14.459.el9_2, kernel-rt-debug-5.14.0-284.174.1.rt14.459.el9_2 +11
  • RHSA-2026:21745 Released 2026-05-28 · Red Hat rating Important
    kernel-rt security update
    • Red Hat Enterprise Linux NFV (v. 8) kernel-rt-4.18.0-553.126.1.rt7.467.el8_10, kernel-rt-core-4.18.0-553.126.1.rt7.467.el8_10, kernel-rt-debug-4.18.0-553.126.1.rt7.467.el8_10 +9
    • Red Hat Enterprise Linux RT (v. 8) kernel-rt-4.18.0-553.126.1.rt7.467.el8_10, kernel-rt-core-4.18.0-553.126.1.rt7.467.el8_10, kernel-rt-debug-4.18.0-553.126.1.rt7.467.el8_10 +7
  • RHSA-2026:21706 Released 2026-05-28 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux BaseOS (v. 8) bpftool-4.18.0-553.126.1.el8_10, kernel-4.18.0-553.126.1.el8_10, kernel-abi-stablelists-4.18.0-553.126.1.el8_10 +19
    • Red Hat Enterprise Linux CRB (v. 8) kernel-tools-libs-devel-4.18.0-553.126.1.el8_10
  • RHSA-2026:21556 Released 2026-05-28 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-687.12.1.el9_8, kernel-64k-debug-devel-matched-5.14.0-687.12.1.el9_8, kernel-64k-devel-5.14.0-687.12.1.el9_8 +12
    • Red Hat Enterprise Linux BaseOS (v. 9) kernel-5.14.0-687.12.1.el9_8, kernel-64k-5.14.0-687.12.1.el9_8, kernel-64k-core-5.14.0-687.12.1.el9_8 +28
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-687.12.1.el9_8, libperf-5.14.0-687.12.1.el9_8
    • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt-5.14.0-687.12.1.el9_8, kernel-rt-64k-5.14.0-687.12.1.el9_8, kernel-rt-64k-core-5.14.0-687.12.1.el9_8 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt-5.14.0-687.12.1.el9_8, kernel-rt-core-5.14.0-687.12.1.el9_8, kernel-rt-debug-5.14.0-687.12.1.el9_8 +9

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 9AffectedNo fix yet
Red Hat CodeReady Linux Builder EUS (v.9.6)Fixed RHSA-2026:23224
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:23329
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:21556
Red Hat Enterprise Linux AppStream E4S (v.9.2)Fixed RHSA-2026:22940
Red Hat Enterprise Linux AppStream E4S (v.9.4)Fixed RHSA-2026:23237
Red Hat Enterprise Linux AppStream EUS (v. 10.0)Fixed RHSA-2026:24343
Red Hat Enterprise Linux AppStream EUS (v.9.6)Fixed RHSA-2026:23224
Red Hat Enterprise Linux BaseOS (v. 10)Fixed RHSA-2026:23329
Red Hat Enterprise Linux BaseOS (v. 8)Fixed RHSA-2026:21706
Red Hat Enterprise Linux BaseOS (v. 9)Fixed RHSA-2026:21556
Red Hat Enterprise Linux BaseOS E4S (v.9.2)Fixed RHSA-2026:22940
Red Hat Enterprise Linux BaseOS E4S (v.9.4)Fixed RHSA-2026:23237
Red Hat Enterprise Linux BaseOS EUS (v. 10.0)Fixed RHSA-2026:24343
Red Hat Enterprise Linux BaseOS EUS (v.9.6)Fixed RHSA-2026:23224
Red Hat Enterprise Linux CRB (v. 8)Fixed RHSA-2026:21706
Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)Fixed RHSA-2026:23329
Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)Fixed RHSA-2026:21556
Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0)Fixed RHSA-2026:24343
Red Hat Enterprise Linux NFV (v. 8)Fixed RHSA-2026:21745
Red Hat Enterprise Linux RT (v. 8)Fixed RHSA-2026:21745
Red Hat Enterprise Linux Real Time (v. 10)Fixed RHSA-2026:23329
Red Hat Enterprise Linux Real Time (v. 9)Fixed RHSA-2026:21556
Red Hat Enterprise Linux Real Time E4S (v.9.2)Fixed RHSA-2026:22900
Red Hat Enterprise Linux Real Time E4S (v.9.4)Fixed RHSA-2026:23237
Red Hat Enterprise Linux Real Time EUS (v. 10.0)Fixed RHSA-2026:24343
Red Hat Enterprise Linux Real Time EUS (v.9.6)Fixed RHSA-2026:23224
Red Hat Enterprise Linux Real Time for NFV (v. 10)Fixed RHSA-2026:23329
Red Hat Enterprise Linux Real Time for NFV (v. 9)Fixed RHSA-2026:21556
Red Hat Enterprise Linux Real Time for NFV E4S (v.9.2)Fixed RHSA-2026:22900
Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4)Fixed RHSA-2026:23237
Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0)Fixed RHSA-2026:24343
Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6)Fixed RHSA-2026:23224
Not affected: 2 products
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-31709
  2. 2026-10-03 Alias added: GHSA-8hp2-qmc6-f97h
  3. 2026-10-16 CISA SSVC decision points changed
  4. 2026-10-16 Priority changed: LOW → MEDIUM
  5. 2026-10-19 Weakness changed · CISA ADP

References

Patch 2

Other 5

  • TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
  • TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
  • TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
  • TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
  • TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
See all 15278 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences