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VulnerabilityPublished Updated

CVE-2026-52915: Linux kernel · netfilter: ip6t_hbh: reject oversized option lists

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.1 High · fixed in db0250470f023f159094052c0bd5ab026a88ae93 : patch Linux kernel soon.

Data as of 26 Oct 2026, 13:47 UTC

CVSS 3.1 base score
7.1High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in db0250470f023f159094052c0bd5ab026a88ae93, 588933f1a2ca5ff99274f8c9f25dc3a25d0191c3, 4322dcde6b4173c2d8e8e6118ed290794263bcc8 +5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 24 Jun 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < db0250470f023f159094052c0bd5ab026a88ae93
Fixed in
  • db0250470f023f159094052c0bd5ab026a88ae93
LinuxLinuxAffected
  • ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 588933f1a2ca5ff99274f8c9f25dc3a25d0191c3
Fixed in
  • 588933f1a2ca5ff99274f8c9f25dc3a25d0191c3
LinuxLinuxAffected
  • ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 4322dcde6b4173c2d8e8e6118ed290794263bcc8
Fixed in
  • 4322dcde6b4173c2d8e8e6118ed290794263bcc8
LinuxLinuxAffected
  • ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 784aadea7a108c9f90985683caa87fb0198c6a39
Fixed in
  • 784aadea7a108c9f90985683caa87fb0198c6a39
LinuxLinuxAffected
  • ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 57b0ac5e1b46f1f0338dff392ef2092e2871b412
Fixed in
  • 57b0ac5e1b46f1f0338dff392ef2092e2871b412
LinuxLinuxAffected
  • ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 41ec2e242f1702e8370ddfe14d22b7a766021c3e
Fixed in
  • 41ec2e242f1702e8370ddfe14d22b7a766021c3e

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: ip6t_hbh: reject oversized option lists struct ip6t_opts stores at most IP6T_OPTS_OPTSNR option descriptors, but hbh_mt6_check() does not reject larger optsnr values supplied from userspace. Validate optsnr in the rule setup path so only match data that fits the fixed-size opts array can be installed. This follows the existing xtables pattern of rejecting invalid user-provided counts in checkentry() and keeps the packet matching path unchanged. `struct ip6t_opts` has a fixed `opts[IP6T_OPTS_OPTSNR]` array, where `IP6T_OPTS_OPTSNR` is 16, then off-by-one array access is possible: [ 137.924693][ T8692] UBSAN: array-index-out-of-bounds in ../net/ipv6/netfilter/ip6t_hbh.c:110:29 [ 137.926167][ T8692] index 16 is out of range for type '__u16 [16]'

References

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