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VulnerabilityPublished Updated

CVE-2026-90037: Linux kernel · NFSD: Prevent client use-after-free during close_lru reaping

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 9.8 Critical · fixed in e57a9ed34ea8c17e831de59b8f1a6b2d80d347a1 : patch Linux kernel as a priority.

Data as of 26 Oct 2026, 13:47 UTC

CVSS 3.1 base score
9.8Critical
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.4% chance of exploitation in 30 days – higher than 41% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in e57a9ed34ea8c17e831de59b8f1a6b2d80d347a1, adc34b5df5c5d87043cb500b0867fc1c4ad0117e, 0763482227822f7343557f086afc382086d56c4c +2
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 16 Sep 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 217526e7ecc9f6f243e976772e81eab7ab986a4c, < e57a9ed34ea8c17e831de59b8f1a6b2d80d347a1
Fixed in
  • e57a9ed34ea8c17e831de59b8f1a6b2d80d347a1
LinuxLinuxAffected
  • ≥ 217526e7ecc9f6f243e976772e81eab7ab986a4c, < adc34b5df5c5d87043cb500b0867fc1c4ad0117e
Fixed in
  • adc34b5df5c5d87043cb500b0867fc1c4ad0117e
LinuxLinuxAffected
  • ≥ 217526e7ecc9f6f243e976772e81eab7ab986a4c, < 0763482227822f7343557f086afc382086d56c4c
Fixed in
  • 0763482227822f7343557f086afc382086d56c4c
LinuxLinuxAffected
  • ≥ 217526e7ecc9f6f243e976772e81eab7ab986a4c, < 2330b788d732f43668b965b3105b37ceb276dfea
Fixed in
  • 2330b788d732f43668b965b3105b37ceb276dfea
LinuxLinuxAffected
  • ≥ 217526e7ecc9f6f243e976772e81eab7ab986a4c, < 83dd59ac1c3455c2c7d8ddb582d980a13199b9b3
Fixed in
  • 83dd59ac1c3455c2c7d8ddb582d980a13199b9b3
LinuxLinuxAffected
  • =3.17
Fixed in–

Description

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.

References

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