CVE-2026-80551: Linux kernel · s390/vfio_ccw: Ensure first IDAW remains constant
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 9.3 Critical · fixed in fc59e9482117ebdccd6dc7fa8082f8b980fd021e : patch Linux kernel as a priority.
Data as of 30 Oct 2026, 13:17 UTC
Thin evidence
One scorer or none| CNA (Linux) | CVSS 3.1 | 9.3 |
|---|
- 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 fc59e9482117ebdccd6dc7fa8082f8b980fd021e, 565bef268d75bf7df665bce6923a88cd0eb74592, 460b977a4e71cc319fdadf91c193ec3beaa57263 +3
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
Weaponized: 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 30 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
AI-suggested
A patch is available and has been applied in the Linux kernel versions identified by the fixed commit hashes. Users should update to a fixed Linux kernel version to remediate this vulnerability. Since this is a kernel-level issue, applying the official kernel update is the recommended mitigation.
Description
CVE-2026-80551 is a critical vulnerability in the Linux kernel's s390/vfio_ccw subsystem. It involves improper handling of the first IDAW (I/O Descriptor Address Word) in a list, which does not need to be aligned on a 2K/4K boundary like subsequent IDAWs. The vulnerability was addressed by ensuring the first IDAW remains constant between reads to maintain a consistent set of IDAWs.
References
- git.kernel.org/stable/c/5b7c23440343e336259cd45017cc901a744c41b0 (opens in a new tab)
- git.kernel.org/stable/c/460b977a4e71cc319fdadf91c193ec3beaa57263 (opens in a new tab)
- git.kernel.org/stable/c/0d46c2565f173bcddcdcaf44a4f69789a20535e2 (opens in a new tab)
- git.kernel.org/stable/c/08ef2a82115690d6e229615872ac1731af732497 (opens in a new tab)
- git.kernel.org/stable/c/fc59e9482117ebdccd6dc7fa8082f8b980fd021e (opens in a new tab)
- git.kernel.org/stable/c/565bef268d75bf7df665bce6923a88cd0eb74592 (opens in a new tab)