net/tcp-ao: fix use-after-free of key in del_async path (CVE-2026-53389) | HOL Guard CVE

High · CVSS 7.8CVE-2026-53389

net/tcp-ao: fix use-after-free of key in del_async path

Answer in brief

CVE-2026-53389 records a High severity (CVSS 7.8) vulnerability in net/tcp-ao: fix use-after-free of key in del_async path. 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 Jul 19, 2026Updated Aug 17, 2026Source checked Sep 20, 2026First seen by HOL Aug 5, 2026Material review Aug 17, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 7.8
Exploitation: Not marked as known exploited
Affected software: 3 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 7.8. 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.

Affected products and reported versions
Product	Affected versions	Fixed versions
cpe:2.3:o:linux:linux_kernel::::::::	Not reported	Not reported

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=d6732b95b6fbbc6d5bb9d2f809e275763640c4a2 <6ce7ef41743740ce15c2061561b784148b565b3f \|\| >=d6732b95b6fbbc6d5bb9d2f809e275763640c4a2 <e77fbefd1269b5c123e7c651a1ebdce1b87d19a0 \|\| >=d6732b95b6fbbc6d5bb9d2f809e275763640c4a2 <7ddc29a094d96e9b3aa280433c6dc443df9eabf2 \|\| >=d6732b95b6fbbc6d5bb9d2f809e275763640c4a2 <5ba9950bc9078e19b69cca1e56d1553b125c6857	6ce7ef41743740ce15c2061561b784148b565b3f, e77fbefd1269b5c123e7c651a1ebdce1b87d19a0, 7ddc29a094d96e9b3aa280433c6dc443df9eabf2, 5ba9950bc9078e19b69cca1e56d1553b125c6857
Linux/Linuxgeneric	6.7	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to 6ce7ef41743740ce15c2061561b784148b565b3f if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Jul 19, 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 5, 2026

Sources and claim methodology

Upstream source description

In the Linux kernel, the following vulnerability has been resolved: net/tcp-ao: fix use-after-free of key in del_async path In tcp_ao_delete_key(), the del_async path skips the current_key and rnext_key validity checks present in the synchronous path, assuming these pointers are always NULL on LISTEN sockets. However, if a key was added with set_current=1/set_rnext=1 while the socket was in CLOSE state, current_key and rnext_key will be non-NULL after listen() transitions the socket to LISTEN. When such a key is deleted with del_async=1, hlist_del_rcu() and call_rcu() free the key without clearing the dangling pointers. After the RCU grace period, getsockopt(TCP_AO_INFO) dereferences current_key->sndid and rnext_key->rcvid from freed slab memory. Clear current_key and rnext_key in the del_async path when they reference the key being deleted.

Quoted source text, attributed separately from HOL analysis.