CVE-2026-80554: Linux kernel · s390/vfio_ccw: Limit the number of channel program segments
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 9.3 Critical.
Data as of 26 Oct 2026, 17:16 UTC
- 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.
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 26 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
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 for this vulnerability has been implemented in the Linux kernel by imposing a limit on the number of channel program segments in the vfio_ccw driver. Users should apply the official kernel updates that include this fix. Since no explicit patch links or vendor advisories are provided here, users should consult their Linux distribution's security advisories (e.g., Ubuntu security notices) for the relevant kernel updates to remediate this issue.
Description
In the Linux kernel, the following vulnerability has been resolved: s390/vfio_ccw: Limit the number of channel program segments The processing of channel programs, and the CCWs within them, is done recursively. As such, there is an arbitrary (but not architectural) limit to the number of CCWs that can exist in a single channel program. The vfio-ccw logic breaks these channel programs into segments whenever it encounters a Transfer-In-Channel (TIC) CCW, and the combined number of segments count towards the global limit. Impose an equivalent limit to the number of segments until such logic can be made non-recursive.
References
- nvd.nist.gov/vuln/detail/CVE-2026-80554 (opens in a new tab)
- git.kernel.org/stable/c/06f4d6e5a8af6c2072e8cd39dbc512c683ca7fb2 (opens in a new tab)
- git.kernel.org/stable/c/15fb4559a7fdf0b8725e433a71cfd03a1313a48b (opens in a new tab)
- git.kernel.org/stable/c/4ee94790490ae8dcc97df8597f07836c8a81bbcf (opens in a new tab)
- git.kernel.org/stable/c/5405c90d6a47b3014e74ee0618a162449abbbc93 (opens in a new tab)
- git.kernel.org/stable/c/a1625f66eaa1200068a0e2c05bc90e65182fc4e3 (opens in a new tab)
- ubuntu.com/security/CVE-2026-80554 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-80554 (opens in a new tab)