Bluetooth: ISO: fix refcounting of iso_conn

Answer in brief

CVE-2026-74534 records a High severity (CVSS 8.8) vulnerability in Bluetooth: ISO: fix refcounting of iso_conn. 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	>=dc26097bdb864a0d5955b9a25e43376ffc1af99b <3b921533e8aa95b77aadcf31737595578e735f3c \|\| >=dc26097bdb864a0d5955b9a25e43376ffc1af99b <8208b4939afb0a1977fffe902c3ca42fe0f3baaa \|\| >=dc26097bdb864a0d5955b9a25e43376ffc1af99b <fdfde532ab1caa165fcd8985001157ac8b4db365 \|\| f53e7489273dc2bb307bf50f319b3762d45534f0 \|\| a58d0f5dac322e16cc75334d000666512341bde5 \|\| >=6.11.11 <6.12 \|\| >=6.12.2 <6.13	3b921533e8aa95b77aadcf31737595578e735f3c, 8208b4939afb0a1977fffe902c3ca42fe0f3baaa, fdfde532ab1caa165fcd8985001157ac8b4db365, 6.12, 6.13
Linux/Linuxgeneric	6.13	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to 3b921533e8aa95b77aadcf31737595578e735f3c 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: fix refcounting of iso_conn iso_conn_del() and iso_chan_del() have a race that results to double-put of iso_conn: [Task hdev->workqueue] [Task 2] iso_conn_del iso_chan_del iso_conn_hold_unless_zero iso_conn_lock iso_conn_lock conn->sk = NULL iso_conn_unlock sk = iso_sock_hold(conn) <---------´ if (!sk) iso_conn_put iso_conn_put iso_conn_put /* UAF */ The extra put for !sk in iso_conn_del() is currently required since failing iso_chan_add() may leave iso_conn not associated with any sk. Fix by having iso_pi(sk)->conn own refcount when non-NULL, so iso_conn_del does not need to put it. Adjust the iso_conn_add() refcounting so that conn is put if it does not get associated with an sk.

Quoted source text, attributed separately from HOL analysis.