Read the docs
TI-2026-33584 Aliases CVE-2026-45859GHSA-v8w5-25mx-q5r4

netfilter: nfnetlink_queue: do shared-unconfirmed check before segmentation

Priority MEDIUM 40CWE-400Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Partial Red Hat: 7 fixed, 2 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-400.

Summary

In the Linux kernel, the following vulnerability has been resolved: netfilter: nfnetlink_queue: do shared-unconfirmed check before segmentation Ulrich reports a regression with nfqueue: If an application did not set the 'F_GSO' capability flag and a gso packet with an unconfirmed nf_conn entry is received all packets are now dropped instead of queued, because the check happens after skb_gso_segment(). In that case, we did have exclusive ownership of the skb and its associated conntrack entry. The elevated use count is due to skb_clone happening via skb_gso_segment(). Move the check so that its peformed vs. the aggregated packet. Then, annotate the individual segments except the first one so we can do a 2nd check at reinject time. For the normal case, where userspace does in-order reinjects, this avoids packet drops: first reinjected segment continues traversal and confirms entry, remaining segments observe the confirmed entry. While at it, simplify nf_ct_drop_unconfirmed(): We only care about unconfirmed entries with a refcnt > 1, there is no need to special-case dying entries. This only happens with UDP. With TCP, the only unconfirmed packet will be the TCP SYN, those aren't aggregated by GRO. Next patch adds a udpgro test case to cover this scenario.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00712 53rd percentileScored 2026-11-07
Fix Partial Linux (Linux): 6.1.191, 6.6.160, 5.16 +5Red Hat: 1 advisoryRed Hat: 7 fixed, 2 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
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
LinuxLinux6.1.107 to before 6.1.191; 6.6.48 to before 6.6.160; 5.15.166 to before 5.16; 6.10.7 to before 6.116.1.191, 6.6.160, 5.16, 6.11Patch availableCNA
LinuxLinux6.11 and later6.1.191, 6.6.160, 6.12.75, 6.18.14, 6.19.4, 7.0Patch availableCNA
  • Linux VendorLinux Affected 6.1.107 to before 6.1.191; 6.6.48 to before 6.6.160; 5.15.166 to before 5.16; 6.10.7 to before 6.11 Fixed in 6.1.191, 6.6.160, 5.16, 6.11 Patch available CNA
  • Linux VendorLinux Affected 6.11 and later Fixed in 6.1.191, 6.6.160, 6.12.75, 6.18.14, 6.19.4, 7.0 Patch available CNA

CPE configurations NVD · 6

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*5.15.166 to before 5.16; 6.1.107 to before 6.2; 6.6.48 to before 6.7; 6.10.7 to before 6.11; 6.11.1 to before 6.12.75; 6.13 to before 6.18.14; 6.19 to before 6.19.4VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.11:-:*:*:*:*:*:*6.11VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.11:rc4:*:*:*:*:*:*6.11 rc4VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.11:rc5:*:*:*:*:*:*6.11 rc5VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.11:rc6:*:*:*:*:*:*6.11 rc6VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.11:rc7:*:*:*:*:*:*6.11 rc7VulnerableLinux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 5.15.166 to before 5.16; 6.1.107 to before 6.2; 6.6.48 to before 6.7; 6.10.7 to before 6.11; 6.11.1 to before 6.12.75; 6.13 to before 6.18.14; 6.19 to before 6.19.4 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.11:-:*:*:*:*:*:* Versions 6.11 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.11:rc4:*:*:*:*:*:* Versions 6.11 rc4 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.11:rc5:*:*:*:*:*:* Versions 6.11 rc5 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.11:rc6:*:*:*:*:*:* Versions 6.11 rc6 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.11:rc7:*:*:*:*:*:* Versions 6.11 rc7 Vulnerable ·Linux

Remediation

  • Fix · CNA Linux (Linux) Fixed in 6.1.191, 6.6.160, 5.16, 6.11
  • Fix · CNA Linux (Linux) Fixed in 6.1.191, 6.6.160, 6.12.75, 6.18.14, 6.19.4, 7.0

Red Hat 1 advisory

  • RHSA-2026:83207 Released 2026-10-15 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • 10Base-SMTV kernel-modules-internal-6.12.0-211.66.1.el10_2
    • Red Hat Enterprise Linux AppStream (v. 10) kernel-64k-debug-devel-6.12.0-211.66.1.el10_2, kernel-64k-debug-devel-matched-6.12.0-211.66.1.el10_2, kernel-64k-devel-6.12.0-211.66.1.el10_2 +12
    • Red Hat Enterprise Linux BaseOS (v. 10) kernel-6.12.0-211.66.1.el10_2, kernel-64k-6.12.0-211.66.1.el10_2, kernel-64k-core-6.12.0-211.66.1.el10_2 +29
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) kernel-tools-libs-devel-6.12.0-211.66.1.el10_2, libperf-6.12.0-211.66.1.el10_2
    • Red Hat Enterprise Linux Hidden (v. 10) kernel-modules-internal-6.12.0-211.66.1.el10_2
    • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt-6.12.0-211.66.1.el10_2, kernel-rt-64k-6.12.0-211.66.1.el10_2, kernel-rt-64k-core-6.12.0-211.66.1.el10_2 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt-6.12.0-211.66.1.el10_2, kernel-rt-core-6.12.0-211.66.1.el10_2, kernel-rt-debug-6.12.0-211.66.1.el10_2 +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 9AffectedNo fix yet
10Base-SMTVFixed RHSA-2026:83207
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:83207
Red Hat Enterprise Linux BaseOS (v. 10)Fixed RHSA-2026:83207
Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)Fixed RHSA-2026:83207
Red Hat Enterprise Linux Hidden (v. 10)Fixed RHSA-2026:83207
Red Hat Enterprise Linux Real Time (v. 10)Fixed RHSA-2026:83207
Red Hat Enterprise Linux Real Time for NFV (v. 10)Fixed RHSA-2026:83207
Not affected: 3 products
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 8
  • Red Hat Enterprise Linux 9

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-45859
  2. 2026-10-03 Alias added: GHSA-v8w5-25mx-q5r4
  3. 2026-10-16 Fix available: RHSA-2026:83207 · Red Hat
  4. 2026-10-16 Fix available: 10Base-SMTV, Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10) +4 · Red Hat
  5. 2026-10-16 CISA SSVC decision points changed
  6. 2026-10-16 Priority changed: LOW → MEDIUM
  7. 2026-10-19 Weakness changed · CISA ADP
  8. 2026-10-21 Fix available: Linux/[email protected], Linux/Linux@aead84bdacd77e08357fd718e5dcaffaf387f3c3 · CNA
  9. 2026-10-21 1 new reference · CNA
  10. 2026-10-25 EPSS moved to the 50th–90th percentile
  11. 2026-10-29 Affected versions changed · Red Hat
  12. 2026-10-30 Fix available: Linux/Linux@4666688657e1054278b836b825fb88b2907e2da2, Linux/[email protected] · CNA
  13. 2026-10-30 1 new reference · CNA
  14. 2026-11-06 CVSS score changed · Red Hat

References

Patch 4

Other 2

  • 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