VulnerabilityPublished 17 Sep 2026Updated 21 Oct 2026

CVE-2026-90162: Linux kernel · ksmbd: defer publishing granted locks to prevent UAF/double-free race

Affects Linux kernelSource CVE Database V5

Not known to be exploited · CVSS 8.8 High · fixed in ff6870cf3b7eccc69d03cbb6f23e3995d96e9a8d : patch Linux kernel soon.

Data as of 26 Oct 2026, 13:47 UTC

CVSS 3.1 base score

8.8High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.6% chance of exploitation in 30 days – higher than 50% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in ff6870cf3b7eccc69d03cbb6f23e3995d96e9a8d, b68d4bb6b03a667c305626bd2c242fd162bac17e, a1d26dfb32919088e3638dca01068df3c4507433 +2

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

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, < ff6870cf3b7eccc69d03cbb6f23e3995d96e9a8d	Fixed in ff6870cf3b7eccc69d03cbb6f23e3995d96e9a8d
LinuxLinux	Affected ≥ e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9, < b68d4bb6b03a667c305626bd2c242fd162bac17e	Fixed in b68d4bb6b03a667c305626bd2c242fd162bac17e
LinuxLinux	Affected ≥ e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9, < a1d26dfb32919088e3638dca01068df3c4507433	Fixed in a1d26dfb32919088e3638dca01068df3c4507433
LinuxLinux	Affected ≥ e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9, < 65f54ed0289e9a57e6c60b14347ccea4c318f1fc	Fixed in 65f54ed0289e9a57e6c60b14347ccea4c318f1fc
LinuxLinux	Affected ≥ e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9, < 29f74f0f2e6df3b393b7b66e810136d0c64e3c59	Fixed in 29f74f0f2e6df3b393b7b66e810136d0c64e3c59
LinuxLinux	Affected =5.15	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: ksmbd: defer publishing granted locks to prevent UAF/double-free race In smb2_lock(), mid-batch granted locks are published to connection-wide (conn->lock_list) and file-wide (fp->lock_list) lists immediately upon vfs_lock_file() success, while also remaining tracked on the stack-local rollback_list. If a subsequent element in the same SMB2_LOCK request array fails validation or execution, the thread jumps to out: and walks rollback_list to undo previously granted locks. However, because the granted lock was already published to conn->lock_list, a concurrent UNLOCK request on the same connection can find the lock object and kfree() it before the rollback loop executes. When the granting thread subsequently walks rollback_list, it dereferences and frees the already-freed ksmbd_lock structure, resulting in a Use-After-Free and Double-Free (on both ksmbd_lock and struct file_lock). Fix this by deferring the publication of granted locks to conn->lock_list and fp->lock_list until after the entire array of lock elements has been processed without error. Mid-batch grants remain tracked exclusively on the request-local rollback_list until the whole batch succeeds, eliminating the race window.

References

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