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TI-2026-33810 Aliases CVE-2026-46086GHSA-qcf5-mj4w-x99v

net: bridge: use a stable FDB dst snapshot in RCU readers

Priority LOW 24CWE-476Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Partial Red Hat: 27 fixed, 3 without a fix

Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-476.

Summary

In the Linux kernel, the following vulnerability has been resolved: net: bridge: use a stable FDB dst snapshot in RCU readers Local FDB entries can be rewritten in place by `fdb_delete_local()`, which updates `f->dst` to another port or to `NULL` while keeping the entry alive. Several bridge RCU readers inspect `f->dst`, including `br_fdb_fillbuf()` through the `brforward_read()` sysfs path. These readers currently load `f->dst` multiple times and can therefore observe inconsistent values across the check and later dereference. In `br_fdb_fillbuf()`, this means a concurrent local-FDB update can change `f->dst` after the NULL check and before the `port_no` dereference, leading to a NULL-ptr-deref. Fix this by taking a single `READ_ONCE()` snapshot of `f->dst` in each affected RCU reader and using that snapshot for the rest of the access sequence. Also publish the in-place `f->dst` updates in `fdb_delete_local()` with `WRITE_ONCE()` so the readers and writer use matching access patterns.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00129 2nd percentileScored 2026-11-07
Fix Partial Linux (Linux): 5.10.259, 5.15.210, 6.1.176 +5Red Hat: 8 advisoriesRed Hat: 27 fixed, 3 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

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

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux3.14 and later5.10.259, 5.15.210, 6.1.176, 6.6.140, 6.12.86, 6.18.27, 7.0.4, 7.1Patch availableCNA
  • Linux VendorLinux Affected 3.14 and later Fixed in 5.10.259, 5.15.210, 6.1.176, 6.6.140, 6.12.86, 6.18.27, 7.0.4, 7.1 Patch available CNA

CPE configurations NVD · 8

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*3.14.1 to before 5.10.259; 5.11 to before 5.15.210; 5.16 to before 6.1.176; 6.2 to before 6.6.140; 6.7 to before 6.12.86; 6.13 to before 6.18.27; 6.19 to before 7.0.4VulnerableLinux
cpe:2.3:o:linux:linux_kernel:3.14:-:*:*:*:*:*:*3.14VulnerableLinux
cpe:2.3:o:linux:linux_kernel:3.14:rc3:*:*:*:*:*:*3.14 rc3VulnerableLinux
cpe:2.3:o:linux:linux_kernel:3.14:rc4:*:*:*:*:*:*3.14 rc4VulnerableLinux
cpe:2.3:o:linux:linux_kernel:3.14:rc5:*:*:*:*:*:*3.14 rc5VulnerableLinux
cpe:2.3:o:linux:linux_kernel:3.14:rc6:*:*:*:*:*:*3.14 rc6VulnerableLinux
cpe:2.3:o:linux:linux_kernel:3.14:rc7:*:*:*:*:*:*3.14 rc7VulnerableLinux
cpe:2.3:o:linux:linux_kernel:3.14:rc8:*:*:*:*:*:*3.14 rc8VulnerableLinux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 3.14.1 to before 5.10.259; 5.11 to before 5.15.210; 5.16 to before 6.1.176; 6.2 to before 6.6.140; 6.7 to before 6.12.86; 6.13 to before 6.18.27; 6.19 to before 7.0.4 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:3.14:-:*:*:*:*:*:* Versions 3.14 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:3.14:rc3:*:*:*:*:*:* Versions 3.14 rc3 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:3.14:rc4:*:*:*:*:*:* Versions 3.14 rc4 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:3.14:rc5:*:*:*:*:*:* Versions 3.14 rc5 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:3.14:rc6:*:*:*:*:*:* Versions 3.14 rc6 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:3.14:rc7:*:*:*:*:*:* Versions 3.14 rc7 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:3.14:rc8:*:*:*:*:*:* Versions 3.14 rc8 Vulnerable ·Linux

Remediation

  • Fix · CNA Linux (Linux) Fixed in 5.10.259, 5.15.210, 6.1.176, 6.6.140, 6.12.86, 6.18.27, 7.0.4, 7.1

Red Hat 8 advisories

  • RHSA-2026:94438 Released 2026-11-03 · Red Hat rating Critical
    kernel security, bug fix, and enhancement update
    • Red Hat CodeReady Linux Builder EUS (v.9.6) kernel-tools-libs-devel-5.14.0-570.154.1.el9_6, libperf-5.14.0-570.154.1.el9_6
    • Red Hat Enterprise Linux AppStream EUS (v.9.6) kernel-64k-debug-devel-5.14.0-570.154.1.el9_6, kernel-64k-debug-devel-matched-5.14.0-570.154.1.el9_6, kernel-64k-devel-5.14.0-570.154.1.el9_6 +12
    • Red Hat Enterprise Linux BaseOS EUS (v.9.6) kernel-5.14.0-570.154.1.el9_6, kernel-64k-5.14.0-570.154.1.el9_6, kernel-64k-core-5.14.0-570.154.1.el9_6 +28
    • Red Hat Enterprise Linux Real Time EUS (v.9.6) kernel-rt-5.14.0-570.154.1.el9_6, kernel-rt-64k-5.14.0-570.154.1.el9_6, kernel-rt-64k-core-5.14.0-570.154.1.el9_6 +21
    • Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6) kernel-rt-5.14.0-570.154.1.el9_6, kernel-rt-core-5.14.0-570.154.1.el9_6, kernel-rt-debug-5.14.0-570.154.1.el9_6 +11
  • RHSA-2026:94109 Released 2026-11-02 · Red Hat rating Critical
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream E4S (v.9.4) kernel-64k-debug-devel-5.14.0-427.161.1.el9_4, kernel-64k-debug-devel-matched-5.14.0-427.161.1.el9_4, kernel-64k-devel-5.14.0-427.161.1.el9_4 +11
    • Red Hat Enterprise Linux BaseOS E4S (v.9.4) bpftool-7.3.0-427.161.1.el9_4, kernel-5.14.0-427.161.1.el9_4, kernel-64k-5.14.0-427.161.1.el9_4 +29
    • Red Hat Enterprise Linux Real Time E4S (v.9.4) kernel-rt-5.14.0-427.161.1.el9_4, kernel-rt-core-5.14.0-427.161.1.el9_4, kernel-rt-debug-5.14.0-427.161.1.el9_4 +9
    • Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4) kernel-rt-5.14.0-427.161.1.el9_4, kernel-rt-core-5.14.0-427.161.1.el9_4, kernel-rt-debug-5.14.0-427.161.1.el9_4 +11
  • RHSA-2026:92997 Released 2026-10-30 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux BaseOS E4S (v.8.8) bpftool-4.18.0-477.177.1.el8_8, kernel-4.18.0-477.177.1.el8_8, kernel-abi-stablelists-4.18.0-477.177.1.el8_8 +14
    • Red Hat Enterprise Linux BaseOS TUS (v.8.8) bpftool-4.18.0-477.177.1.el8_8, kernel-4.18.0-477.177.1.el8_8, kernel-abi-stablelists-4.18.0-477.177.1.el8_8 +14
Show 5 more Red Hat advisories
  • RHSA-2026:91493 Released 2026-10-28 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux BaseOS AUS (v.8.6) bpftool-4.18.0-372.225.1.el8_6, kernel-4.18.0-372.225.1.el8_6, kernel-abi-stablelists-4.18.0-372.225.1.el8_6 +14
    • Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.6) bpftool-4.18.0-372.225.1.el8_6, kernel-4.18.0-372.225.1.el8_6, kernel-abi-stablelists-4.18.0-372.225.1.el8_6 +14
  • RHSA-2026:47017 Released 2026-07-28 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream (v. 10) kernel-64k-debug-devel-6.12.0-211.40.1.el10_2, kernel-64k-debug-devel-matched-6.12.0-211.40.1.el10_2, kernel-64k-devel-6.12.0-211.40.1.el10_2 +12
    • Red Hat Enterprise Linux BaseOS (v. 10) kernel-6.12.0-211.40.1.el10_2, kernel-64k-6.12.0-211.40.1.el10_2, kernel-64k-core-6.12.0-211.40.1.el10_2 +29
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) kernel-tools-libs-devel-6.12.0-211.40.1.el10_2, libperf-6.12.0-211.40.1.el10_2
    • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt-6.12.0-211.40.1.el10_2, kernel-rt-64k-6.12.0-211.40.1.el10_2, kernel-rt-64k-core-6.12.0-211.40.1.el10_2 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt-6.12.0-211.40.1.el10_2, kernel-rt-core-6.12.0-211.40.1.el10_2, kernel-rt-debug-6.12.0-211.40.1.el10_2 +9
  • RHSA-2026:39179 Released 2026-07-14 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux BaseOS (v. 8) bpftool-4.18.0-553.144.1.el8_10, kernel-4.18.0-553.144.1.el8_10, kernel-abi-stablelists-4.18.0-553.144.1.el8_10 +19
    • Red Hat Enterprise Linux CRB (v. 8) kernel-tools-libs-devel-4.18.0-553.144.1.el8_10
  • RHSA-2026:39180 Released 2026-07-14 · Red Hat rating Important
    kernel-rt security update
    • Red Hat Enterprise Linux NFV (v. 8) kernel-rt-4.18.0-553.144.1.rt7.485.el8_10, kernel-rt-core-4.18.0-553.144.1.rt7.485.el8_10, kernel-rt-debug-4.18.0-553.144.1.rt7.485.el8_10 +9
    • Red Hat Enterprise Linux RT (v. 8) kernel-rt-4.18.0-553.144.1.rt7.485.el8_10, kernel-rt-core-4.18.0-553.144.1.rt7.485.el8_10, kernel-rt-debug-4.18.0-553.144.1.rt7.485.el8_10 +7
  • RHSA-2026:38491 Released 2026-07-13 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-687.25.1.el9_8, kernel-64k-debug-devel-matched-5.14.0-687.25.1.el9_8, kernel-64k-devel-5.14.0-687.25.1.el9_8 +12
    • Red Hat Enterprise Linux BaseOS (v. 9) kernel-5.14.0-687.25.1.el9_8, kernel-64k-5.14.0-687.25.1.el9_8, kernel-64k-core-5.14.0-687.25.1.el9_8 +28
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-687.25.1.el9_8, libperf-5.14.0-687.25.1.el9_8
    • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt-5.14.0-687.25.1.el9_8, kernel-rt-64k-5.14.0-687.25.1.el9_8, kernel-rt-64k-core-5.14.0-687.25.1.el9_8 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt-5.14.0-687.25.1.el9_8, kernel-rt-core-5.14.0-687.25.1.el9_8, kernel-rt-debug-5.14.0-687.25.1.el9_8 +9

Vendor assessments

Red Hat

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

ProductStatusPlan or fix
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 7AffectedNo fix yet
Red Hat Enterprise Linux 9AffectedNo fix yet: Fix deferred
Red Hat CodeReady Linux Builder EUS (v.9.6)Fixed RHSA-2026:94438
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:47017
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:38491
Red Hat Enterprise Linux AppStream E4S (v.9.4)Fixed RHSA-2026:94109
Red Hat Enterprise Linux AppStream EUS (v.9.6)Fixed RHSA-2026:94438
Red Hat Enterprise Linux BaseOS (v. 10)Fixed RHSA-2026:47017
Red Hat Enterprise Linux BaseOS (v. 8)Fixed RHSA-2026:39179
Red Hat Enterprise Linux BaseOS (v. 9)Fixed RHSA-2026:38491
Red Hat Enterprise Linux BaseOS AUS (v.8.6)Fixed RHSA-2026:91493
Red Hat Enterprise Linux BaseOS E4S (v.8.8)Fixed RHSA-2026:92997
Red Hat Enterprise Linux BaseOS E4S (v.9.4)Fixed RHSA-2026:94109
Red Hat Enterprise Linux BaseOS EUS (v.9.6)Fixed RHSA-2026:94438
Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.6)Fixed RHSA-2026:91493
Red Hat Enterprise Linux BaseOS TUS (v.8.8)Fixed RHSA-2026:92997
Red Hat Enterprise Linux CRB (v. 8)Fixed RHSA-2026:39179
Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)Fixed RHSA-2026:47017
Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)Fixed RHSA-2026:38491
Red Hat Enterprise Linux NFV (v. 8)Fixed RHSA-2026:39180
Red Hat Enterprise Linux RT (v. 8)Fixed RHSA-2026:39180
Red Hat Enterprise Linux Real Time (v. 10)Fixed RHSA-2026:47017
Red Hat Enterprise Linux Real Time (v. 9)Fixed RHSA-2026:38491
Red Hat Enterprise Linux Real Time E4S (v.9.4)Fixed RHSA-2026:94109
Red Hat Enterprise Linux Real Time EUS (v.9.6)Fixed RHSA-2026:94438
Red Hat Enterprise Linux Real Time for NFV (v. 10)Fixed RHSA-2026:47017
Red Hat Enterprise Linux Real Time for NFV (v. 9)Fixed RHSA-2026:38491
Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4)Fixed RHSA-2026:94109
Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6)Fixed RHSA-2026:94438

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-46086
  2. 2026-10-03 Alias added: GHSA-qcf5-mj4w-x99v
  3. 2026-10-29 Fix available: RHSA-2026:91493 · Red Hat
  4. 2026-10-30 Fix available: Red Hat Enterprise Linux BaseOS AUS (v.8.6), Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.6) · Red Hat
  5. 2026-10-30 Fix available: Red Hat Enterprise Linux BaseOS E4S (v.8.8), Red Hat Enterprise Linux BaseOS TUS (v.8.8) · Red Hat
  6. 2026-10-31 Fix available: RHSA-2026:92997 · Red Hat
  7. 2026-11-03 Fix available: RHSA-2026:94109 · Red Hat
  8. 2026-11-03 Fix available: Red Hat Enterprise Linux AppStream E4S (v.9.4), Red Hat Enterprise Linux BaseOS E4S (v.9.4), Red Hat Enterprise Linux Real Time E4S (v.9.4) +1 · Red Hat
  9. 2026-11-03 Affected versions changed · Red Hat
  10. 2026-11-03 CVSS score changed · Red Hat
  11. 2026-11-03 Fix available: RHSA-2026:94438 · Red Hat
  12. 2026-11-03 Fix available: Red Hat CodeReady Linux Builder EUS (v.9.6), Red Hat Enterprise Linux AppStream EUS (v.9.6), Red Hat Enterprise Linux BaseOS EUS (v.9.6) +2 · Red Hat
  13. 2026-11-06 CISA SSVC decision points changed

References

Patch 8

  • 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