Microsoft security update for CVE-2026-64523 — azl3 kernel
🔗 CVE IDs covered (1)
📋 Microsoft's advisory
EchelonGraph does not copy Microsoft's advisory page: its FAQ and remediation text are not shown here. Read the advisory on https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-64523. This page also shows what EchelonGraph holds for CVE-2026-64523, with the description from its CVE record, which the CVE Numbering Authority that assigned the CVE wrote: for a CVE Microsoft assigned, often in the words of Microsoft's own advisory.
🎯 Affected products6
- azl3 kernel 6.6.144.1-1 on Azure Linux 3.0
- azl3 kernel 6.6.145.2-1 on Azure Linux 3.0
- azl3 kernel 6.6.150.1-1 on Azure Linux 3.0
- azl3 kernel 6.6.152.1-1 on Azure Linux 3.0
- azl3 kernel 6.6.157.1-1 on Azure Linux 3.0
- azl3 kernel 6.6.159.1-1 on Azure Linux 3.0
✅ Updates Microsoft lists: 2 updates
2 rows: one per KB article or update, update type and fixed build. Their details are on Microsoft's advisory.
| KB article | Update | Fixed build |
|---|---|---|
| — | Security Update | — |
| — | Security Update | 6.6.161.1-1 |
🧭 EchelonGraph on CVE-2026-64523
- EchelonGraph score
- 9.8 CRITICAL
- CISA KEV
- Not listed
- Fix status
- A fix is available — apply it.
Description from the CVE record (CVE.org), as published by its numbering authority
In the Linux kernel, the following vulnerability has been resolved: net/handshake: Take a long-lived file reference at submit handshake_nl_accept_doit() needs the file pointer backing req->hr_sk->sk_socket to survive the window between handshake_req_next() and the subsequent FD_PREPARE() and get_file(). The submit-side sock_hold() does not provide that. sk_refcnt keeps struct sock alive, but struct socket is owned by sock->file: when the consumer fputs the last file reference, sock_release() tears the socket down regardless of any sock_hold. Add an hr_file pointer to struct handshake_req and acquire an explicit reference on sock->file during handshake_req_submit(). handshake_complete() and handshake_req_cancel() release the reference on the completion-bit-winning path. The submit error path must also release the file reference, but after rhashtable insertion a concurrent handshake_req_cancel() can discover the request and race the error path. Gate the error-path cleanup -- sk_destruct restoration, fput, and request destruction -- with test_and_set_bit(HANDSHAKE_F_REQ_COMPLETED), the same serialization handshake_complete() and handshake_req_cancel() already use. When cancel has already claimed ownership, the submit error path returns without touching the request; socket teardown handles final destruction. The accept-side dereferences are not yet retargeted; that change comes in the next patch.
Published by kernel.org, the CVE Numbering Authority that assigned CVE-2026-64523, in its CVE record at CVE.org; reused under the CVE Program's Terms of Use (its licence and MITRE's copyright notice are in our Terms of Service).