CVE-2026-112934VulnerabilityPublished 29 Oct 2026

shodan · filelock: SoftReadWriteLock holder refresh writes through a hard link and hangs on a named pipe that another local

Affects shodanSource GCVE Database

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Authoritative record:CVE-2026-112934· Medium 6.1

Not known to be exploited · CVSS 6.1 Medium : upgrade to 1.31.0_12 when convenient.

Data as of 30 Oct 2026, 05:17 UTC

CVSS 3.1 base score

6.1Medium

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

Thin evidence

One scorer or none

CVSS scores by source
CNA (GitHub_M)	CVSS 3.1	6.1

Patch: Available – fixed in 1.31.0_12

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

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

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: 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: None: There is no loss of confidentiality within the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on 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 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 shodan to 1.31.0_12.

Affected software

Product	Affected	Fixed in
Homebrewshodan`pkg:brew/shodan`Other threats	Affected >=1.31.0_11 <1.31.0_12	Fixed in 1.31.0_12

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 1.31.0_12 that addresses this vulnerability. Users should upgrade to this fixed version to remediate the issue. No additional mitigation steps are required if the patch is applied. If upgrading is not immediately possible, restricting local user write access to the lock's .rw directory and ensuring the system enforces protections against unauthorized hard links (e.g., enabling fs.protected_hardlinks=1 on Linux) can reduce risk, but the primary remediation is to apply the official fix.

Description

CVE-2026-112934 describes a vulnerability in filelock versions >=1.31.0_11 and <1.31.0_12 where the SoftReadWriteLock holder refresh mechanism can be manipulated by a local user who owns the lock's .rw directory tree. This user can cause the lock user's process to hang indefinitely by placing a FIFO (named pipe) in the holders directory, blocking write operations and preventing heartbeat refreshes. Additionally, on systems that permit hard links to files not owned by the user (e.g., Linux with fs.protected_hardlinks=0), the attacker can cause the lock user to overwrite part of one of its own private files. The vulnerability has no confidentiality impact but can cause integrity degradation and high availability impact by allowing two processes to believe they hold the write lock simultaneously. A fix is available in version 1.31.0_12.

Impact

The vulnerability allows a local attacker with ownership of the lock's .rw directory to cause denial of service by hanging the lock user's process during lock acquisition or refresh, preventing heartbeat refreshes and causing the lock to be granted to multiple processes simultaneously. This results in a high availability impact. There is no confidentiality impact. Integrity impact is low and limited to overwriting the first ~135 bytes of a private file with the holder record data on systems that permit hard links to files not owned by the user. The attack requires local user privileges and ownership of the lock directory, and does not require user interaction.

Summary

The vulnerability arises from the SoftReadWriteLock and AsyncSoftReadWriteLock implementations refreshing their holder records by reopening and writing to files under <path>.rw/holders/ without verifying the file type beyond symbolic links. A local attacker who owns the lock's .rw directory can rename a FIFO or hard link over the holder record file. Opening a FIFO for writing blocks indefinitely if no reader exists, causing the lock user's write_lock() or read_lock() calls to hang and the heartbeat thread to stop without triggering the on_compromise callback. This leads to a stale lock state where multiple processes believe they hold the lock. On kernels that allow hard links to files not owned by the user, the attacker can cause the lock user to overwrite the first ~135 bytes of one of its private files with the holder record data. The issue affects filelock versions >=1.31.0_11 and <1.31.0_12 and is rated medium severity with CVSS 6.1. The vulnerability requires local access and ownership of the lock's .rw directory tree, which can occur in sticky world-writable directories like /tmp or directories without the sticky bit. The vendor has released a fix in version 1.31.0_12.

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Affected software

Description

AI analysisMachine-generated, updated 30 Oct 2026, 05:17 UTC

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