Bluetooth: ISO: hold sk properly in iso_conn_ready (CVE-2026-74537) | HOL Guard CVE

High · CVSS 8.8CVE-2026-74537

Bluetooth: ISO: hold sk properly in iso_conn_ready

Answer in brief

CVE-2026-74537 records a High severity (CVSS 8.8) vulnerability in Bluetooth: ISO: hold sk properly in iso_conn_ready. 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 15, 2026Updated Aug 17, 2026Source checked Sep 29, 2026First seen by HOL Aug 15, 2026Material review Aug 17, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 8.8
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 8.8. 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	>=27c24fda62b601d6f9ca5e992502578c4310876f <4e9b5e8669b3602a4e01b6d1e9539b72e42c84d5 \|\| >=27c24fda62b601d6f9ca5e992502578c4310876f <1308d72903d792d10b82bc4ef08b8a4452308b04 \|\| >=27c24fda62b601d6f9ca5e992502578c4310876f <0d255e63fcf3f13a570d7ac11678fa1164ac015c	4e9b5e8669b3602a4e01b6d1e9539b72e42c84d5, 1308d72903d792d10b82bc4ef08b8a4452308b04, 0d255e63fcf3f13a570d7ac11678fa1164ac015c
Linux/Linuxgeneric	5.15	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to 4e9b5e8669b3602a4e01b6d1e9539b72e42c84d5 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 15, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 17, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 15, 2026

Sources and claim methodology

Upstream source description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: ISO: hold sk properly in iso_conn_ready sk deref in iso_conn_ready must be done either under conn->lock, or holding a refcount, to avoid concurrent close. conn->sk is currently accessed without either: [Task 1] [Task 2] iso_sock_release iso_conn_ready sk = conn->sk lock_sock(sk) conn->sk = NULL lock_sock(sk) release_sock(sk) iso_sock_kill(sk) UAF on sk deref Fix possible UAF by holding sk refcount in iso_conn_ready(). Also recheck after lock_sock that the socket is still valid. Adjust locking so conn->sk is cleared only under lock_sock.

Quoted source text, attributed separately from HOL analysis.