CVE-2026-112939VulnerabilityPublished 29 Oct 2026

mlx-lm · filelock: SoftFileLock removes a live holder's marker when another user forges the PID in a writable marker

Affects mlx-lmSource GCVE Database

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Authoritative record:CVE-2026-112939· Medium 4.7

Not known to be exploited · CVSS 4.7 Medium : upgrade to 0.32.2_1 when convenient.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 3.1 base score

4.7Medium

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

EPSS: 0.1% chance of exploitation in 30 days – higher than 3% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 0.32.2_1

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

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

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

Attack Vector: Local: The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or remotely (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., tricking a legitimate user into opening a malicious document).
Attack Complexity: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
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: None: There is no loss of confidentiality within the impacted component.
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: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 20 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 29 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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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 mlx-lm to 0.32.2_1.

Affected software

Product	Affected	Fixed in
Homebrewmlx-lm`pkg:brew/mlx-lm`Other threats	Affected >=0.31.0 <0.32.2_1	Fixed in 0.32.2_1

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A patch is available in filelock version 0.32.2_1 that addresses this vulnerability. Users should upgrade to this fixed version. Until patched, avoid creating lock marker files with group or other write permissions in sticky or non-removable directories. Using the default umask 022 or ensuring marker files are not writable by other users mitigates the risk. No other actions are required if the patch is applied.

Description

A vulnerability in filelock versions 3.22.0 through 4.2.0 allows a local user with write access to a lock marker file (but not removal rights) to forge the process ID in the marker. This causes another process running as the lock owner or root to mistakenly consider the lock stale and remove the live marker, resulting in two processes simultaneously holding the lock and potentially corrupting the protected resource. The issue arises when the marker file is created with group or other write permissions, typically due to an explicit mode or permissive umask settings in a sticky or non-removable directory.

Impact

An attacker with local write access to the lock marker file but no removal rights can cause two processes to simultaneously hold the lock, violating the lock's integrity guarantees. This can lead to concurrent writes to the protected resource without error, potentially corrupting data. There is no confidentiality or availability impact. The attack requires local access and specific file permission conditions, making exploitation complex.

Summary

The SoftFileLock and related classes rely on marker files to indicate lock ownership by a process ID (PID). They determine if a lock is stale by reading the PID in the marker file without verifying who wrote it. If a local user can write to the marker file but cannot remove it (due to sticky directory permissions), they can overwrite the PID with a dead process ID. Subsequently, a contender process running as the lock owner or root will treat the lock as stale, remove the live marker, and acquire the lock. This leads to simultaneous lock holders and potential integrity violations. The vulnerability affects filelock versions from 3.22.0 (when stale lock detection was introduced) through 4.2.0. The flaw requires specific conditions: writable marker files with group or other write bits set, a sticky or non-removable directory preventing marker removal by the attacker, and a contender process running as the lock owner or root. The default umask 022 is not affected. The issue is tracked as CVE-2026-112939 and has a CVSS 3.1 score of 4.7 (Medium). A fix is available in version 0.32.2_1.

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Affected software

Description

AI analysisMachine-generated, updated 30 Oct 2026, 06:30 UTC

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