VulnerabilityPublished 17 Sep 2026Updated 21 Oct 2026

CVE-2026-90167: Linux kernel · ksmbd: serialize oplock close with pending break ownership

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in dc1e34f78dfab755fab9ad820ac5f82348fe1792 : update Linux kernel when convenient.

Data as of 26 Oct 2026, 17:30 UTC

Severity

Unrated

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.2% chance of exploitation in 30 days – higher than 10% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in dc1e34f78dfab755fab9ad820ac5f82348fe1792, b0148dc5625dbfd50596ac63c7487c12e8a8ab03, 7148a6c06ddf1c263a1cf422bee541f24d3d3926 +2

Exploitation evidence

Disclosed: evidence found.
CVE published 17 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9, < dc1e34f78dfab755fab9ad820ac5f82348fe1792	Fixed in dc1e34f78dfab755fab9ad820ac5f82348fe1792
LinuxLinux	Affected ≥ e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9, < b0148dc5625dbfd50596ac63c7487c12e8a8ab03	Fixed in b0148dc5625dbfd50596ac63c7487c12e8a8ab03
LinuxLinux	Affected ≥ e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9, < 7148a6c06ddf1c263a1cf422bee541f24d3d3926	Fixed in 7148a6c06ddf1c263a1cf422bee541f24d3d3926
LinuxLinux	Affected ≥ e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9, < 7d6e682b7633120c2f93400b8c6f335d9d8e5318	Fixed in 7d6e682b7633120c2f93400b8c6f335d9d8e5318
LinuxLinux	Affected ≥ e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9, < 5f97bac88bfb333f426f01c118b8235e75af8d96	Fixed in 5f97bac88bfb333f426f01c118b8235e75af8d96
LinuxLinux	Affected =5.15	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: ksmbd: serialize oplock close with pending break ownership close may abort an in-flight oplock break while another breaker already holds an opinfo reference. Releasing pending_break wakes that waiter, but without serializing the close transition with bit acquisition it can become a new break owner through the test_and_set_bit() fast path. It can then overwrite OPLOCK_CLOSING with OPLOCK_ACK_WAIT and continue a break for a dying opinfo. Make OPLOCK_CLOSING terminal once the opinfo is removed from the inode list. Serialize that transition, pending_break acquisition, and OPLOCK_ACK_WAIT setup with an opinfo state lock. A breaker which loses the race releases its ownership and returns -ENOENT. Explicitly wake pending_break waiters during close so they can observe the terminal state. Also prevent ACK and timeout paths from replacing OPLOCK_CLOSING with OPLOCK_STATE_NONE.

References

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