NFSD: Prevent client use-after-free during close_lru reaping
CVE-2026-90037 · published 16 Sept 2026
How serious is it
- Severity: critical, CVSS score 9.8 out of 10.
- No exploit prediction (EPSS) score yet.
- Not on the CISA list of exploited vulnerabilities.
- No public exploit in Exploit-DB.
Is your app affected by CVE-2026-90037?
Paste this prompt into Claude Code, Cursor or any AI coding tool: it runs a free Shippable scan of your project and fixes what it finds. Built with Lovable, Bolt or v0? Scan your live app. Or upload your package file.
Who is affected
- Linux Linux: 217526e7ecc9f6f243e976772e81eab7ab986a4c to < adc34b5df5c5d87043cb500b0867fc1c4ad0117e, 217526e7ecc9f6f243e976772e81eab7ab986a4c to < 0763482227822f7343557f086afc382086d56c4c, 217526e7ecc9f6f243e976772e81eab7ab986a4c to < 83dd59ac1c3455c2c7d8ddb582d980a13199b9b3, 217526e7ecc9f6f243e976772e81eab7ab986a4c to < e57a9ed34ea8c17e831de59b8f1a6b2d80d347a1
- Linux Linux: 3.17
How to check
- Find out whether you run the affected product and which version, then compare it with the versions above.
How to fix
Copies a prompt for Claude Code, Cursor or Codex that asks it to check whether you run this product.
- Apply the vendor's update or mitigation from the references below. If there is none yet, limit exposure of the affected service until there is.
- If a vulnerable version was live, check your logs and rotate the secrets that server could read.
The advisory
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.
Check your whole app
Dependencies are only half of it. Free and read-only: before you push, run npx shippable-dev scan localhost:3000 in your project folder, no account needed. For your live app, you prove it's yours with a one-line tag first.
References
- git.kernel.org/stable/c/adc34b5df5c5d87043cb500b0867fc1c4ad0117e
- git.kernel.org/stable/c/0763482227822f7343557f086afc382086d56c4c
- git.kernel.org/stable/c/83dd59ac1c3455c2c7d8ddb582d980a13199b9b3
- git.kernel.org/stable/c/e57a9ed34ea8c17e831de59b8f1a6b2d80d347a1
- git.kernel.org/stable/c/2330b788d732f43668b965b3105b37ceb276dfea
Merged from CVE List. Last updated 26 Oct 2026. All vulnerabilities · RSS · JSON