CVE-2026-80548: Linux kernel · s390/vfio_ccw: Selectively expand io_mutex
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 8.8 High.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 7% 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 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 has been implemented that expands the scope of the io_mutex lock in the Linux kernel s390/vfio_ccw driver to prevent race conditions. Users should apply the official kernel updates that include this patch. Since this is a kernel-level fix, upgrading to a patched kernel version is the recommended remediation.
Description
In the Linux kernel, the following vulnerability has been resolved: s390/vfio_ccw: Selectively expand io_mutex The io_mutex was defined to serialize the io_regions, but then has also sort of been associated with the I/O themselves because of the close relationship they share. With the handful of races that are possible, the choices are either to: A) expand the scope of io_mutex to close these remaining windows, or B) reduce the scope of io_mutex to just io_region, and introduce a new lock mechanism for the remaining I/O resources This patch implements A, since B brings with it a lot more interactions that would need to be tracked and kept in a correct hierarchy. It also takes advantage of the workqueue element for cp_free() that now gets called out of fsm_notoper(), which could be invoked out of an interrupt context and thus cannot acquire a mutex itself.
References
- nvd.nist.gov/vuln/detail/CVE-2026-80548 (opens in a new tab)
- git.kernel.org/stable/c/2a5ac0c0f1f7da33929211a2e41911bf72ee35d8 (opens in a new tab)
- git.kernel.org/stable/c/2ba9efdf9ebedc4e54df4b56aa3b43a65f7967cd (opens in a new tab)
- git.kernel.org/stable/c/34f4feff3e90bd09308fad0974e97113b23b812a (opens in a new tab)
- git.kernel.org/stable/c/b6aecea4b2b246f9fbd98a5712daa1193a60818e (opens in a new tab)
- git.kernel.org/stable/c/f72a51810d49411bd8cad0c2df8592320a2fe5cc (opens in a new tab)
- ubuntu.com/security/CVE-2026-80548 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-80548 (opens in a new tab)
- git.kernel.org/stable/c/56d7488533ceac4e986e96e15c9e487a2245bc01 (opens in a new tab)
- git.kernel.org/stable/c/dab6a6627b0b0cce23653e99c7b0bf8c6cfd82e0 (opens in a new tab)