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VulnerabilityPublished Updated

CVE-2026-72423: Linux kernel · bpf: Guard conntrack opts error writes

Affects Linux kernelSource CVE Database V5

0

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

CVSS 3.1 base score
8.8High
How severe the flaw is on the 0–10 CVSS scale.
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:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 15 Aug 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
  • ≥ b4c2b9593a1c4c3a718370e34af28e817fd5e5c6, < dd74c80203842a21b2ebb9f70d1260d9aa20fa05
Fixed in
  • dd74c80203842a21b2ebb9f70d1260d9aa20fa05
LinuxLinuxAffected
  • ≥ b4c2b9593a1c4c3a718370e34af28e817fd5e5c6, < 669bc3b345712112d3f033a1953f5a10b15e7c65
Fixed in
  • 669bc3b345712112d3f033a1953f5a10b15e7c65
LinuxLinuxAffected
  • ≥ b4c2b9593a1c4c3a718370e34af28e817fd5e5c6, < 453f4f1e90de55b6bc297936031b68bef93f2e28
Fixed in
  • 453f4f1e90de55b6bc297936031b68bef93f2e28
LinuxLinuxAffected
  • ≥ b4c2b9593a1c4c3a718370e34af28e817fd5e5c6, < 63d95c6bbd6fc0e411404188306a1fea456300b0
Fixed in
  • 63d95c6bbd6fc0e411404188306a1fea456300b0
LinuxLinuxAffected
  • ≥ b4c2b9593a1c4c3a718370e34af28e817fd5e5c6, < 6f6183a39533d727deaa5061cadae6dd9e6744d0
Fixed in
  • 6f6183a39533d727deaa5061cadae6dd9e6744d0
LinuxLinuxAffected
  • =5.18
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

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