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TI-2026-31412 Aliases CVE-2026-43233GHSA-qx8f-4v7p-9m35

netfilter: nf_conntrack_h323: fix OOB read in decode_choice()

Priority MEDIUM 42CWE-125Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
Low · None · High
Fix status
Partial Red Hat: 9 fixed, 3 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: fix OOB read in decode_choice() In decode_choice(), the boundary check before get_len() uses the variable `len`, which is still 0 from its initialization at the top of the function: unsigned int type, ext, len = 0; ... if (ext || (son->attr & OPEN)) { BYTE_ALIGN(bs); if (nf_h323_error_boundary(bs, len, 0)) /* len is 0 here */ return H323_ERROR_BOUND; len = get_len(bs); /* OOB read */ When the bitstream is exactly consumed (bs->cur == bs->end), the check nf_h323_error_boundary(bs, 0, 0) evaluates to (bs->cur + 0 > bs->end), which is false. The subsequent get_len() call then dereferences *bs->cur++, reading 1 byte past the end of the buffer. If that byte has bit 7 set, get_len() reads a second byte as well. This can be triggered remotely by sending a crafted Q.931 SETUP message with a User-User Information Element containing exactly 2 bytes of PER-encoded data ({0x08, 0x00}) to port 1720 through a firewall with the nf_conntrack_h323 helper active. The decoder fully consumes the PER buffer before reaching this code path, resulting in a 1-2 byte heap-buffer-overflow read confirmed by AddressSanitizer. Fix this by checking for 2 bytes (the maximum that get_len() may read) instead of the uninitialized `len`. This matches the pattern used at every other get_len() call site in the same file, where the caller checks for 2 bytes of available data before calling get_len().

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00463 40th percentileScored 2026-11-07
Fix Partial Linux (Linux): 5.10.252, 5.15.202, 6.1.165 +5Red Hat: 3 advisoriesRed Hat: 9 fixed, 3 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
LinuxLinux4.15 and later5.10.252, 5.15.202, 6.1.165, 6.6.128, 6.12.75, 6.18.16, 6.19.6, 7.0Patch availableCNA
  • Linux VendorLinux Affected 4.15 and later Fixed in 5.10.252, 5.15.202, 6.1.165, 6.6.128, 6.12.75, 6.18.16, 6.19.6, 7.0 Patch available CNA

CPE configurations NVD · 9

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*4.15.1 to before 5.10.252; 5.11 to before 5.15.202; 5.16 to before 6.1.165; 6.2 to before 6.6.128; 6.7 to before 6.12.75; 6.13 to before 6.18.16; 6.19 to before 6.19.6VulnerableLinux
cpe:2.3:o:linux:linux_kernel:4.15:-:*:*:*:*:*:*4.15VulnerableLinux
cpe:2.3:o:linux:linux_kernel:4.15:rc4:*:*:*:*:*:*4.15 rc4VulnerableLinux
cpe:2.3:o:linux:linux_kernel:4.15:rc5:*:*:*:*:*:*4.15 rc5VulnerableLinux
cpe:2.3:o:linux:linux_kernel:4.15:rc6:*:*:*:*:*:*4.15 rc6VulnerableLinux
cpe:2.3:o:linux:linux_kernel:4.15:rc7:*:*:*:*:*:*4.15 rc7VulnerableLinux
cpe:2.3:o:linux:linux_kernel:4.15:rc8:*:*:*:*:*:*4.15 rc8VulnerableLinux
cpe:2.3:o:linux:linux_kernel:4.15:rc9:*:*:*:*:*:*4.15 rc9VulnerableLinux
cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*7.0 rc1VulnerableLinux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 4.15.1 to before 5.10.252; 5.11 to before 5.15.202; 5.16 to before 6.1.165; 6.2 to before 6.6.128; 6.7 to before 6.12.75; 6.13 to before 6.18.16; 6.19 to before 6.19.6 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:4.15:-:*:*:*:*:*:* Versions 4.15 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:4.15:rc4:*:*:*:*:*:* Versions 4.15 rc4 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:4.15:rc5:*:*:*:*:*:* Versions 4.15 rc5 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:4.15:rc6:*:*:*:*:*:* Versions 4.15 rc6 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:4.15:rc7:*:*:*:*:*:* Versions 4.15 rc7 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:4.15:rc8:*:*:*:*:*:* Versions 4.15 rc8 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:4.15:rc9:*:*:*:*:*:* Versions 4.15 rc9 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:* Versions 7.0 rc1 Vulnerable ·Linux

Remediation

  • Fix · CNA Linux (Linux) Fixed in 5.10.252, 5.15.202, 6.1.165, 6.6.128, 6.12.75, 6.18.16, 6.19.6, 7.0

Red Hat 3 advisories

  • RHSA-2026:68531 Released 2026-09-17 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux BaseOS (v. 8) bpftool-4.18.0-553.164.1.el8_10, kernel-4.18.0-553.164.1.el8_10, kernel-abi-stablelists-4.18.0-553.164.1.el8_10 +19
    • Red Hat Enterprise Linux CRB (v. 8) kernel-tools-libs-devel-4.18.0-553.164.1.el8_10
  • RHSA-2026:68532 Released 2026-09-17 · Red Hat rating Important
    kernel-rt security update
    • Red Hat Enterprise Linux NFV (v. 8) kernel-rt-4.18.0-553.164.1.rt7.505.el8_10, kernel-rt-core-4.18.0-553.164.1.rt7.505.el8_10, kernel-rt-debug-4.18.0-553.164.1.rt7.505.el8_10 +9
    • Red Hat Enterprise Linux RT (v. 8) kernel-rt-4.18.0-553.164.1.rt7.505.el8_10, kernel-rt-core-4.18.0-553.164.1.rt7.505.el8_10, kernel-rt-debug-4.18.0-553.164.1.rt7.505.el8_10 +7
  • RHSA-2026:57252 Released 2026-08-20 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-687.41.1.el9_8, kernel-64k-debug-devel-matched-5.14.0-687.41.1.el9_8, kernel-64k-devel-5.14.0-687.41.1.el9_8 +12
    • Red Hat Enterprise Linux BaseOS (v. 9) kernel-5.14.0-687.41.1.el9_8, kernel-64k-5.14.0-687.41.1.el9_8, kernel-64k-core-5.14.0-687.41.1.el9_8 +28
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-687.41.1.el9_8, libperf-5.14.0-687.41.1.el9_8
    • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt-5.14.0-687.41.1.el9_8, kernel-rt-64k-5.14.0-687.41.1.el9_8, kernel-rt-64k-core-5.14.0-687.41.1.el9_8 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt-5.14.0-687.41.1.el9_8, kernel-rt-core-5.14.0-687.41.1.el9_8, kernel-rt-debug-5.14.0-687.41.1.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 10AffectedNo fix yet
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 9AffectedNo fix yet
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:57252
Red Hat Enterprise Linux BaseOS (v. 8)Fixed RHSA-2026:68531
Red Hat Enterprise Linux BaseOS (v. 9)Fixed RHSA-2026:57252
Red Hat Enterprise Linux CRB (v. 8)Fixed RHSA-2026:68531
Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)Fixed RHSA-2026:57252
Red Hat Enterprise Linux NFV (v. 8)Fixed RHSA-2026:68532
Red Hat Enterprise Linux RT (v. 8)Fixed RHSA-2026:68532
Red Hat Enterprise Linux Real Time (v. 9)Fixed RHSA-2026:57252
Red Hat Enterprise Linux Real Time for NFV (v. 9)Fixed RHSA-2026:57252
Not affected: 1 product
  • Red Hat Enterprise Linux 7

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-43233
  2. 2026-10-03 Alias added: GHSA-qx8f-4v7p-9m35
  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 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