CVE-2026-52915: Linux kernel · netfilter: ip6t_hbh: reject oversized option lists
Affects Linux kernelSource CVE Database V5
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
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 24 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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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
- git.kernel.org/stable/c/2d523ba48d4ecc46acfb6aba548292cfcce1ac02 (opens in a new tab)
- git.kernel.org/stable/c/588933f1a2ca5ff99274f8c9f25dc3a25d0191c3 (opens in a new tab)
- git.kernel.org/stable/c/784aadea7a108c9f90985683caa87fb0198c6a39 (opens in a new tab)
- git.kernel.org/stable/c/41ec2e242f1702e8370ddfe14d22b7a766021c3e (opens in a new tab)
- git.kernel.org/stable/c/db0250470f023f159094052c0bd5ab026a88ae93 (opens in a new tab)
- git.kernel.org/stable/c/57b0ac5e1b46f1f0338dff392ef2092e2871b412 (opens in a new tab)
- git.kernel.org/stable/c/6feb43c0995ab3a9c826707eb46541a1696fe4f7 (opens in a new tab)
- git.kernel.org/stable/c/4322dcde6b4173c2d8e8e6118ed290794263bcc8 (opens in a new tab)