Microsoft security update for CVE-2026-90037
🔗 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-2026-90037. This page also shows what EchelonGraph holds for CVE-2026-90037, 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 products5
- 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
- azl4 kernel 6.18.50-1.5.azl4 on Azure Linux 4.0
✅ Updates Microsoft lists: 4 updates
4 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 | — |
| — | Security Update | 6.6.161.1-1 |
| — | Security Update | 0:6.18.57-1.1.azl4 |
🧭 EchelonGraph on CVE-2026-90037
- 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: NFSD: Prevent client use-after-free during close_lru reaping An nfs4_openowner left on nn->close_lru after its final CLOSE keeps its last closed stateid in oo_last_closed_stid, holding only a raw pointer to its nfs4_client. The laundromat reaps timed-out entries, drops nn->client_lock, and calls nfs4_put_stid(), which dereferences the client through cl_lock. Nothing pins the client across that window, so a concurrent force_expire_client() can free it and nfs4_put_stid() reads freed memory. __destroy_client() hits the same race, walking clp->cl_openowners without cl_lock. Pin the client with cl_rpc_users before dropping client_lock, and skip clients already expiring. __destroy_client() then cleans up its own close_lru entries through release_last_closed_stateid(), so teardown no longer races the laundromat.
Published by kernel.org, the CVE Numbering Authority that assigned CVE-2026-90037, 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).