Review reviewCritical

CVE-2026-64459

Linux

In the Linux kernel, the following vulnerability has been resolved: tcp: restore RCU grace period in tcp_ao_destroy_sock Commit 51e547e8c89c ("tcp: Free TCP-AO/TCP-MD5 info/keys without RCU") removed the call_rcu() callback from tcp_ao_destroy_sock(), arguing that "the destruction of info/keys is delayed until the socket destructor" and therefore "no one can discover it anymore". That argument does not hold for the call site in tcp_connect() (net/ipv4/tcp_output.c:4327-4332). At that point the socket is in TCP_SYN_SENT, has already been inserted into the inet ehash by inet_hash_connect() in...

CVSS: 9.8
EPSS: -
CISA KEV: Not listed
Published: 2026.07.25

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability-

Technical severityCVSS 9.8

Vulnerability overview

Affected product and versions

Product: Linux
Affected versions: >= 51e547e8c89c661f6fbede4a28b1d33b13625683 < 657646c08c94ef7b9dbe468fe7828032216f9841, >= 51e547e8c89c661f6fbede4a28b1d33b13625683 < 4caf12c778fed3dc3824cf36263be5e2c491fbd0, >= 51e547e8c89c661f6fbede4a28b1d33b13625683 < 8bc4d43bccbd60efe85d0a44d5bf41762f2f0c30, >= 6.18
Fixed versions: No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that Linux and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE: Not available