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TI-2026-18890 Aliases CVE-2026-23455GHSA-gm78-p64f-gx97

netfilter: nf_conntrack_h323: check for zero length in DecodeQ931()

Priority MEDIUM 48CWE-125Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
High · None · High
Fix status
Partial Red Hat: 41 fixed, 2 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: netfilter: nf_conntrack_h323: check for zero length in DecodeQ931() In DecodeQ931(), the UserUserIE code path reads a 16-bit length from the packet, then decrements it by 1 to skip the protocol discriminator byte before passing it to DecodeH323_UserInformation(). If the encoded length is 0, the decrement wraps to -1, which is then passed as a large value to the decoder, leading to an out-of-bounds read. Add a check to ensure len is positive after the decrement.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.01587 75th percentileScored 2026-11-07
Fix Partial Linux (Linux): 5.10.253, 5.15.203, 6.1.167 +5Red Hat: 14 advisoriesRed Hat: 41 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
LinuxLinux2.6.17 and later5.10.253, 5.15.203, 6.1.167, 6.6.130, 6.12.78, 6.18.20, 6.19.10, 7.0Patch availableCNA
  • Linux VendorLinux Affected 2.6.17 and later Fixed in 5.10.253, 5.15.203, 6.1.167, 6.6.130, 6.12.78, 6.18.20, 6.19.10, 7.0 Patch available CNA

CPE configurations NVD · 5

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*2.6.17 to before 5.10.253; 5.11 to before 5.15.203; 5.16 to before 6.1.167; 6.2 to before 6.6.130; 6.7 to before 6.12.78; 6.13 to before 6.18.20; 6.19 to before 6.19.10VulnerableLinux
cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*7.0 rc1VulnerableLinux
cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*7.0 rc2VulnerableLinux
cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*7.0 rc3VulnerableLinux
cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*7.0 rc4VulnerableLinux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 2.6.17 to before 5.10.253; 5.11 to before 5.15.203; 5.16 to before 6.1.167; 6.2 to before 6.6.130; 6.7 to before 6.12.78; 6.13 to before 6.18.20; 6.19 to before 6.19.10 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:* Versions 7.0 rc1 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:* Versions 7.0 rc2 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:* Versions 7.0 rc3 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:* Versions 7.0 rc4 Vulnerable ·Linux

Remediation

  • Fix · CNA Linux (Linux) Fixed in 5.10.253, 5.15.203, 6.1.167, 6.6.130, 6.12.78, 6.18.20, 6.19.10, 7.0

Red Hat 14 advisories

  • RHSA-2026:55445 Released 2026-08-17 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream EUS (v. 10.0) kernel-64k-debug-devel-6.12.0-55.98.1.el10_0, kernel-64k-debug-devel-matched-6.12.0-55.98.1.el10_0, kernel-64k-devel-6.12.0-55.98.1.el10_0 +12
    • Red Hat Enterprise Linux BaseOS EUS (v. 10.0) kernel-6.12.0-55.98.1.el10_0, kernel-64k-6.12.0-55.98.1.el10_0, kernel-64k-core-6.12.0-55.98.1.el10_0 +28
    • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) kernel-tools-libs-devel-6.12.0-55.98.1.el10_0, libperf-6.12.0-55.98.1.el10_0
    • Red Hat Enterprise Linux Real Time EUS (v. 10.0) kernel-rt-6.12.0-55.98.1.el10_0, kernel-rt-64k-6.12.0-55.98.1.el10_0, kernel-rt-64k-core-6.12.0-55.98.1.el10_0 +21
    • Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0) kernel-rt-6.12.0-55.98.1.el10_0, kernel-rt-core-6.12.0-55.98.1.el10_0, kernel-rt-debug-6.12.0-55.98.1.el10_0 +11
  • RHSA-2026:41236 Released 2026-07-17 · Red Hat rating Critical
    kernel-rt security, bug fix, and enhancement update
    • Red Hat Enterprise Linux for Real Time (v. 7 ELS) kernel-rt-3.10.0-1160.155.1.rt56.1307.el7, kernel-rt-debug-3.10.0-1160.155.1.rt56.1307.el7, kernel-rt-debug-devel-3.10.0-1160.155.1.rt56.1307.el7 +4
  • RHSA-2026:35896 Released 2026-07-06 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux BaseOS AUS (v.8.4) bpftool-4.18.0-305.197.1.el8_4, kernel-4.18.0-305.197.1.el8_4, kernel-abi-stablelists-4.18.0-305.197.1.el8_4 +14
    • Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4) bpftool-4.18.0-305.197.1.el8_4, kernel-4.18.0-305.197.1.el8_4, kernel-abi-stablelists-4.18.0-305.197.1.el8_4 +14
Show 11 more Red Hat advisories
  • RHSA-2026:35863 Released 2026-07-06 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux BaseOS E4S (v.8.8) bpftool-4.18.0-477.150.1.el8_8, kernel-4.18.0-477.150.1.el8_8, kernel-abi-stablelists-4.18.0-477.150.1.el8_8 +14
    • Red Hat Enterprise Linux BaseOS TUS (v.8.8) bpftool-4.18.0-477.150.1.el8_8, kernel-4.18.0-477.150.1.el8_8, kernel-abi-stablelists-4.18.0-477.150.1.el8_8 +14
  • RHSA-2026:35844 Released 2026-07-06 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux Server (v. 7 ELS) bpftool-3.10.0-1160.154.1.el7, kernel-3.10.0-1160.154.1.el7, kernel-abi-whitelists-3.10.0-1160.154.1.el7 +11
    • Red Hat Enterprise Linux Server Optional (v. 7 ELS) kernel-debug-devel-3.10.0-1160.154.1.el7, kernel-tools-libs-devel-3.10.0-1160.154.1.el7
  • RHSA-2026:33899 Released 2026-07-01 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux BaseOS AUS (v.8.6) bpftool-4.18.0-372.198.1.el8_6, kernel-4.18.0-372.198.1.el8_6, kernel-abi-stablelists-4.18.0-372.198.1.el8_6 +14
    • Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.6) bpftool-4.18.0-372.198.1.el8_6, kernel-4.18.0-372.198.1.el8_6, kernel-abi-stablelists-4.18.0-372.198.1.el8_6 +14
  • RHSA-2026:27713 Released 2026-06-22 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream E4S (v.9.4) kernel-64k-debug-devel-5.14.0-427.134.1.el9_4, kernel-64k-debug-devel-matched-5.14.0-427.134.1.el9_4, kernel-64k-devel-5.14.0-427.134.1.el9_4 +11
    • Red Hat Enterprise Linux BaseOS E4S (v.9.4) bpftool-7.3.0-427.134.1.el9_4, kernel-5.14.0-427.134.1.el9_4, kernel-64k-5.14.0-427.134.1.el9_4 +29
    • Red Hat Enterprise Linux Real Time E4S (v.9.4) kernel-rt-5.14.0-427.134.1.el9_4, kernel-rt-core-5.14.0-427.134.1.el9_4, kernel-rt-debug-5.14.0-427.134.1.el9_4 +9
    • Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4) kernel-rt-5.14.0-427.134.1.el9_4, kernel-rt-core-5.14.0-427.134.1.el9_4, kernel-rt-debug-5.14.0-427.134.1.el9_4 +11
  • RHSA-2026:26515 Released 2026-06-17 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux AppStream E4S (v.9.2) kernel-64k-debug-devel-5.14.0-284.176.1.el9_2, kernel-64k-debug-devel-matched-5.14.0-284.176.1.el9_2, kernel-64k-devel-5.14.0-284.176.1.el9_2 +10
    • Red Hat Enterprise Linux BaseOS E4S (v.9.2) bpftool-7.0.0-284.176.1.el9_2, kernel-5.14.0-284.176.1.el9_2, kernel-64k-5.14.0-284.176.1.el9_2 +29
  • RHSA-2026:26462 Released 2026-06-17 · Red Hat rating Important
    kernel-rt security update
    • Red Hat Enterprise Linux Real Time E4S (v.9.2) kernel-rt-5.14.0-284.176.1.rt14.461.el9_2, kernel-rt-core-5.14.0-284.176.1.rt14.461.el9_2, kernel-rt-debug-5.14.0-284.176.1.rt14.461.el9_2 +9
    • Red Hat Enterprise Linux Real Time for NFV E4S (v.9.2) kernel-rt-5.14.0-284.176.1.rt14.461.el9_2, kernel-rt-core-5.14.0-284.176.1.rt14.461.el9_2, kernel-rt-debug-5.14.0-284.176.1.rt14.461.el9_2 +11
  • RHSA-2026:25218 Released 2026-06-11 · Red Hat rating Important
    kernel security update
    • Red Hat CodeReady Linux Builder EUS (v.9.6) kernel-tools-libs-devel-5.14.0-570.120.1.el9_6, libperf-5.14.0-570.120.1.el9_6
    • Red Hat Enterprise Linux AppStream EUS (v.9.6) kernel-64k-debug-devel-5.14.0-570.120.1.el9_6, kernel-64k-debug-devel-matched-5.14.0-570.120.1.el9_6, kernel-64k-devel-5.14.0-570.120.1.el9_6 +12
    • Red Hat Enterprise Linux BaseOS EUS (v.9.6) kernel-5.14.0-570.120.1.el9_6, kernel-64k-5.14.0-570.120.1.el9_6, kernel-64k-core-5.14.0-570.120.1.el9_6 +28
    • Red Hat Enterprise Linux Real Time EUS (v.9.6) kernel-rt-5.14.0-570.120.1.el9_6, kernel-rt-64k-5.14.0-570.120.1.el9_6, kernel-rt-64k-core-5.14.0-570.120.1.el9_6 +21
    • Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6) kernel-rt-5.14.0-570.120.1.el9_6, kernel-rt-core-5.14.0-570.120.1.el9_6, kernel-rt-debug-5.14.0-570.120.1.el9_6 +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
  • RHSA-2026:21557 Released 2026-05-28 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux AppStream (v. 10) kernel-64k-debug-devel-6.12.0-211.18.1.el10_2, kernel-64k-debug-devel-matched-6.12.0-211.18.1.el10_2, kernel-64k-devel-6.12.0-211.18.1.el10_2 +12
    • Red Hat Enterprise Linux BaseOS (v. 10) kernel-6.12.0-211.18.1.el10_2, kernel-64k-6.12.0-211.18.1.el10_2, kernel-64k-core-6.12.0-211.18.1.el10_2 +29
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) kernel-tools-libs-devel-6.12.0-211.18.1.el10_2, libperf-6.12.0-211.18.1.el10_2
    • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt-6.12.0-211.18.1.el10_2, kernel-rt-64k-6.12.0-211.18.1.el10_2, kernel-rt-64k-core-6.12.0-211.18.1.el10_2 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt-6.12.0-211.18.1.el10_2, kernel-rt-core-6.12.0-211.18.1.el10_2, kernel-rt-debug-6.12.0-211.18.1.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
Red Hat CodeReady Linux Builder EUS (v.9.6)Fixed RHSA-2026:25218
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:21557
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:21556
Red Hat Enterprise Linux AppStream E4S (v.9.2)Fixed RHSA-2026:26515
Red Hat Enterprise Linux AppStream E4S (v.9.4)Fixed RHSA-2026:27713
Red Hat Enterprise Linux AppStream EUS (v. 10.0)Fixed RHSA-2026:55445
Red Hat Enterprise Linux AppStream EUS (v.9.6)Fixed RHSA-2026:25218
Red Hat Enterprise Linux BaseOS (v. 10)Fixed RHSA-2026:21557
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 AUS (v.8.4)Fixed RHSA-2026:35896
Red Hat Enterprise Linux BaseOS AUS (v.8.6)Fixed RHSA-2026:33899
Red Hat Enterprise Linux BaseOS E4S (v.8.8)Fixed RHSA-2026:35863
Red Hat Enterprise Linux BaseOS E4S (v.9.2)Fixed RHSA-2026:26515
Red Hat Enterprise Linux BaseOS E4S (v.9.4)Fixed RHSA-2026:27713
Red Hat Enterprise Linux BaseOS EUS (v. 10.0)Fixed RHSA-2026:55445
Red Hat Enterprise Linux BaseOS EUS (v.9.6)Fixed RHSA-2026:25218
Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4)Fixed RHSA-2026:35896
Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.6)Fixed RHSA-2026:33899
Red Hat Enterprise Linux BaseOS TUS (v.8.8)Fixed RHSA-2026:35863
Red Hat Enterprise Linux CRB (v. 8)Fixed RHSA-2026:21706
Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)Fixed RHSA-2026:21557
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-2026:55445
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-2026:21557
Red Hat Enterprise Linux Real Time (v. 9)Fixed RHSA-2026:21556
Red Hat Enterprise Linux Real Time E4S (v.9.2)Fixed RHSA-2026:26462
Red Hat Enterprise Linux Real Time E4S (v.9.4)Fixed RHSA-2026:27713
Red Hat Enterprise Linux Real Time EUS (v. 10.0)Fixed RHSA-2026:55445
Red Hat Enterprise Linux Real Time EUS (v.9.6)Fixed RHSA-2026:25218
Red Hat Enterprise Linux Real Time for NFV (v. 10)Fixed RHSA-2026:21557
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-2026:26462
Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4)Fixed RHSA-2026:27713
Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0)Fixed RHSA-2026:55445
Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6)Fixed RHSA-2026:25218
Red Hat Enterprise Linux Server (v. 7 ELS)Fixed RHSA-2026:35844
Red Hat Enterprise Linux Server Optional (v. 7 ELS)Fixed RHSA-2026:35844
Red Hat Enterprise Linux for Real Time (v. 7 ELS)Fixed RHSA-2026:41236

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-23455
  2. 2026-10-03 Alias added: GHSA-gm78-p64f-gx97
  3. 2026-10-16 CISA SSVC decision points changed
  4. 2026-10-19 Weakness changed · CISA ADP

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