SEPTEMBER 8, 2026
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Case File

CVE-2026-53389

HIGH · CVSS 7.8 EPSS 0.13%

Source: NVD + CISA KEV + EPSS · Published 2026-07-19 · Last synced 2026-08-18

CyberRota Analysis

AI-Generated

The vulnerability affects the Linux kernel's TCP Authentication Option (TCP-AO) implementation, specifically in the asynchronous deletion of keys, which can lead to a use-after-free condition. This flaw allows attackers to potentially exploit freed memory references, resulting in undefined behavior or system crashes. Organizations using Linux systems, particularly those implementing TCP-AO, should prioritize patching this vulnerability to mitigate the risk of exploitation.

CVE
CVE-2026-53389
Severity
HIGH
CVSS
7.8
EPSS
0.13%
Linux

Original NVD 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.

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