xen/xenbus: check otherend_id only after it has been initialized (CVE-2026-90310) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-90310

xen/xenbus: check otherend_id only after it has been initialized

Answer in brief

CVE-2026-90310 records a Unknown severity vulnerability in xen/xenbus: check otherend_id only after it has been initialized. 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 Sep 17, 2026Updated Sep 17, 2026Source checked Sep 17, 2026First seen by HOL Sep 17, 2026Material review Sep 17, 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	>=e2dcf9065536ab4a1b00828ff0d19f7d282dfecc <36fb592af353c55832e2cafe3fcfc3291be05f19 \|\| >=e2dcf9065536ab4a1b00828ff0d19f7d282dfecc <c76cbf348c7df077f93fa99a1225a527ce64cfa1	36fb592af353c55832e2cafe3fcfc3291be05f19, c76cbf348c7df077f93fa99a1225a527ce64cfa1
Linux/Linuxgeneric	7.0	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to 36fb592af353c55832e2cafe3fcfc3291be05f19 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 17, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 17, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 17, 2026

Sources and claim methodology

Upstream source description

In the Linux kernel, the following vulnerability has been resolved: xen/xenbus: check otherend_id only after it has been initialized When device just got initialized (for example on module load), the otherend_id field is initialized only after xenbus_read_otherend_details() gets called. If xenstore watch triggers xenbus_dev_changed() before that, it might consider still zeroed otherend_id field (not matching actual xenstore content) as a sign of device state reset. It can happen because xenstore watch are handled in another thread (xenwatch), which can run in parallel to the initial device probe running at module load. In that case, it would call device_unregister(), which would deadlock against device probe from module init. Fix this by considering dev->otherend_id change only after dev->otherend is set (which happen after otherend_id is initialized).

Quoted source text, attributed separately from HOL analysis.