CVE-2026-80921: Linux kernel · KVM: s390: vsie: zero stale crypto bits
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 8.8 High.
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.
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 9 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.
AI-suggested
A fix has been implemented in the Linux kernel to zero out the stale crypto bits, resolving the vulnerability. Users and administrators should apply the official Linux kernel updates that include this patch. Since no explicit patch links or vendor advisories are provided here, verify and obtain the fix from the official Linux kernel sources or trusted vendor updates. There is no indication of known exploits in the wild at this time.
Description
In the Linux kernel, the following vulnerability has been resolved: KVM: s390: vsie: zero stale crypto bits When shadowing crypto access bits from a format0 apcb (crycb 0 or 1), the bits 64..255 are unchanged from whatever is in the vsie page in the crycb and thus in the apcb. This gives a nested guest potential access to a device no longer available. Zero out the remaining bits.
References
- nvd.nist.gov/vuln/detail/CVE-2026-80921 (opens in a new tab)
- git.kernel.org/stable/c/087c19cc60a8caa1a08e1e434c8be2caf6c27733 (opens in a new tab)
- git.kernel.org/stable/c/29b4f7bc2991313bd3e6f6fb8fdf1b173f086dd6 (opens in a new tab)
- git.kernel.org/stable/c/34d5b5b646c91cfb9338d7a12c955a70ffb8c66b (opens in a new tab)
- git.kernel.org/stable/c/59d51550b5cb916bda037673a721a404b3b47a0d (opens in a new tab)
- git.kernel.org/stable/c/7d23489f51109e3ebba5b5db8c5f0185af7b7fdf (opens in a new tab)
- git.kernel.org/stable/c/935eeba276012916c76243e5cbb843efd8fdb75d (opens in a new tab)
- git.kernel.org/stable/c/d110b3297f11ef227098b8a82ade2d5f123b7d2f (opens in a new tab)
- git.kernel.org/stable/c/d4bcd2df6d0d2af916b4fe1a533958778ea7c45b (opens in a new tab)
- git.kernel.org/stable/c/f6079dca67eccb5eabef9f72437948c66dc5131f (opens in a new tab)
- ubuntu.com/security/CVE-2026-80921 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-80921 (opens in a new tab)
- git.kernel.org/linus/34d5b5b646c91cfb9338d7a12c955a70ffb8c66b (opens in a new tab)