CVE-2026-72423: Linux kernel · bpf: Guard conntrack opts error writes
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 8.8 High · fixed in dd74c80203842a21b2ebb9f70d1260d9aa20fa05 : patch Linux kernel soon.
Data as of 26 Oct 2026, 13:47 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 6% 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
- Total control over the software or total information disclosure
CISA SSVC assessment, 2026-10-16.
- Patch
- Available – fixed in dd74c80203842a21b2ebb9f70d1260d9aa20fa05, 669bc3b345712112d3f033a1953f5a10b15e7c65, 453f4f1e90de55b6bc297936031b68bef93f2e28 +2
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 15 Aug 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– |
Description
In the Linux kernel, the following vulnerability has been resolved: bpf: Guard conntrack opts error writes The conntrack lookup and allocation kfuncs take an opts pointer together with an opts__sz argument. The verifier checks only the memory range described by opts__sz, but the wrappers unconditionally write opts->error whenever the internal lookup or allocation helper returns an error. For an invalid size smaller than the end of opts->error, that write can land outside the verifier-checked range. Keep returning NULL for invalid arguments, but only report the error through opts->error when the supplied size includes the field. This preserves error reporting for the supported 12-byte and 16-byte layouts, and for other invalid sizes that still include opts->error.
References
- git.kernel.org/stable/c/669bc3b345712112d3f033a1953f5a10b15e7c65 (opens in a new tab)
- git.kernel.org/stable/c/63d95c6bbd6fc0e411404188306a1fea456300b0 (opens in a new tab)
- git.kernel.org/stable/c/453f4f1e90de55b6bc297936031b68bef93f2e28 (opens in a new tab)
- git.kernel.org/stable/c/dd74c80203842a21b2ebb9f70d1260d9aa20fa05 (opens in a new tab)
- git.kernel.org/stable/c/6f6183a39533d727deaa5061cadae6dd9e6744d0 (opens in a new tab)