CVE Catalog

CVE-2026-53389

HighCVSS 7.8
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.13%

3th percentile - higher than 3% of all known CVEs

Summary

A use-after-free vulnerability was found in the Linux kernel's TCP-AO implementation. In the del_async path of key deletion, the current_key and rnext_key pointers are not cleared, causing a reference to freed memory after the RCU grace period.

Risk Assessment

An attacker could exploit this vulnerability to read or write freed kernel memory, potentially leading to privilege escalation or sensitive data leakage.

Recommendation

It is recommended to immediately update the Linux kernel to a version containing the fix that clears the current_key and rnext_key pointers in the del_async path.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS