s390/vfio_ccw: Selectively expand io_mutex

Answer in brief

CVE-2026-80548 records a Unknown severity vulnerability in s390/vfio_ccw: Selectively expand io_mutex. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 26, 2026Updated Aug 26, 2026Source checked Aug 26, 2026First seen by HOL Aug 26, 2026Material review Aug 26, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=4f76617378ee97c557b526cb58d3c61eb0a9c963 <f72a51810d49411bd8cad0c2df8592320a2fe5cc \|\| >=4f76617378ee97c557b526cb58d3c61eb0a9c963 <2ba9efdf9ebedc4e54df4b56aa3b43a65f7967cd \|\| >=4f76617378ee97c557b526cb58d3c61eb0a9c963 <b6aecea4b2b246f9fbd98a5712daa1193a60818e \|\| >=4f76617378ee97c557b526cb58d3c61eb0a9c963 <2a5ac0c0f1f7da33929211a2e41911bf72ee35d8 \|\| >=4f76617378ee97c557b526cb58d3c61eb0a9c963 <34f4feff3e90bd09308fad0974e97113b23b812a	f72a51810d49411bd8cad0c2df8592320a2fe5cc, 2ba9efdf9ebedc4e54df4b56aa3b43a65f7967cd, b6aecea4b2b246f9fbd98a5712daa1193a60818e, 2a5ac0c0f1f7da33929211a2e41911bf72ee35d8, 34f4feff3e90bd09308fad0974e97113b23b812a
Linux/Linuxgeneric	5.2	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to f72a51810d49411bd8cad0c2df8592320a2fe5cc if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 26, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 26, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 26, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.