CVE-2026-80843: Linux kernel · xfrm: fix xfrm_state_construct() auth-trunc leak
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 26 Oct 2026, 13:47 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 9% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Exploitation evidence
Disclosed: evidence found.
CVE published 4 Sep 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
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
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.
References
- nvd.nist.gov/vuln/detail/CVE-2026-80843 (opens in a new tab)
- git.kernel.org/stable/c/37426395cb90ef217beec8407a14bd82153793d3 (opens in a new tab)
- git.kernel.org/stable/c/71d42da01740ec6557837bebec0bc48cfc3b4c39 (opens in a new tab)
- git.kernel.org/stable/c/958ae9f261319e1cdc44879886bcda2263258cca (opens in a new tab)
- git.kernel.org/stable/c/ba0c110c205855b3f1e3130d8c0fdb484d704c8c (opens in a new tab)
- git.kernel.org/stable/c/be19d20e53a239572bb2a28efcc1cd2b069b1ef9 (opens in a new tab)
- git.kernel.org/stable/c/c12cbf56320fb633484ee0ca1fb7d68d6b64b213 (opens in a new tab)
- git.kernel.org/stable/c/c8837bbe792257af547fd1c0252553ce13148795 (opens in a new tab)
- git.kernel.org/stable/c/cf67361e78dca488d6e4df8396a53e6745a3a80e (opens in a new tab)
- git.kernel.org/stable/c/fb7f3e74789a3c89647f4eb768f6dfaf4a751e72 (opens in a new tab)
- ubuntu.com/security/CVE-2026-80843 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-80843 (opens in a new tab)
- git.kernel.org/linus/c12cbf56320fb633484ee0ca1fb7d68d6b64b213 (opens in a new tab)