CVE-2026-80843
In the Linux kernel, the following vulnerability has been resolved: xfrm: fix xfrm_state_construct() auth-trunc leak attach_auth_trunc() can allocate x->aalg while leaving x->props.aalgo at zero when the selected auth algorithm has no sadb_alg_id. One real case is cmac(aes). xfrm_state_construct() then treats !x->props.aalgo as "no auth algorithm attached yet" and calls attach_auth(). That overwrites x->aalg and loses the first allocation. Any later failure or teardown only frees the replacement pointer. Check whether x->aalg is already attached instead of inferring that state from x->props.aalgo.
Affected versions
Linux kernel versions
2.6.33
and later are affected. Fixed in
5.10.269,
5.15.220,
6.1.187,
6.6.156,
6.12.108,
6.18.49,
7.1.13,
7.2.3,
7.3
and their respective stable series.
References
9 totalFrequently asked questions
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What is CVE-2026-80843?
CVE-2026-80843 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 2.6.33 onward and has been patched in 5.10.269, 5.15.220, 6.1.187 and others. CVE-2026-80843 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2026-80843?
Yes. CVE-2026-80843 has been patched. Fixed versions include 5.10.269, 5.15.220, 6.1.187 and others. If you are running Linux kernel 2.6.33 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-80843 actively exploited?
No. CVE-2026-80843 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.