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Vulnerabilities

Vulnerability · CVE-2026-112908

filelock: StrictSoftFileLock creates its claim directories without the lock mode, so another local user with a write bit on them can end a live hold

Published Oct 28, 2026 · catalog updated Oct 28, 2026 · Red Hat Red Hat Enterprise Linux

Last checked Nov 7, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-112908. EPSS is 0.12%. Act only if a listed version of Red Hat Red Hat Enterprise Linux is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Medium5.3
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.12%
Remediation
Version ranges on file
Affected products
pip filelock · pypi filelock

and apply the caller's to the sentinel (the lock file at ) and to both claim files (the files whose presence says a process wants or holds the lock). They create the two directories that hold the claims, and , with a bare . That gives filtered through the umask (a per-process mask that removes permission bits from new files and directories) or, under a parent with a default ACL (an access control list on a directory that sets the permissions of entries created inside it), through that ACL. A hold consists of two claim names in that directory, which has no sticky bit (a directory flag that lets only a file's owner remove it). When the environment leaves another local user (the other user below) a write bit on the directory, that user can unlink the holder's claims. Three settings do this: umask in a sticky directory such as , umask with the other user in the directory's group, or a default ACL on the lock's parent that grants the group write (the kernel then ignores the umask). After the unlink, the next contender of the holder's account finds the directory empty and enters. The first holder keeps reporting and later releases with no error. Affected versions: filelock >= 3.30.0 and <= 4.2.0 (finding ). ## Severity **CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:L, 5.3 (Medium).** (local): the other user needs an account on the same host. (high attack complexity): the holder must pass a restrictive while its umask or the parent's default ACL leaves the other user a write bit on new directories, and a contender of the holder's account must ask for the lock after the claims are gone. With the common umask and no default ACL the directories are , and the kernel refuses the other user's unlink. (low privileges): an unprivileged account is enough. (no user interaction): the holder's processes act on their own. (no confidentiality impact): the claim files stay unreadable. (high integrity impact): two holders then write the data the lock protects, and neither learns of the othe

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • pip filelock>= 3.30.0, <= 4.2.0
  • pypi filelockversion unspecified

How to fix CVE-2026-112908

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-112908. EPSS is 0.12%. Act only if a listed version of Red Hat Red Hat Enterprise Linux is installed.

Which versions are affected?

Compare what you have installed with >= 3.30.0, <= 4.2.0. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-279; CWE-732: Incorrect Permission Assignment for Critical Resource. EPSS 0.12%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 28, 2026 · GitHub Advisory Database

    Detected

    and apply the caller's to the sentinel (the lock file at ) and to both claim files (the files whose presence says a process wants or holds the lock). They create the two directories that hold the claims, and , with a bare . That gives filtered through the umask (a per-process mask that removes permission bits from new files and directories) or, under a parent with a default ACL (an access control

  2. Oct 28, 2026 · GitHub Advisory Database

    Updated

    and apply the caller's to the sentinel (the lock file at ) and to both claim files (the files whose presence says a process wants or holds the lock). They create the two directories that hold the claims, and , with a bare . That gives filtered through the umask (a per-process mask that removes permission bits from new files and directories) or, under a parent with a default ACL (an access control

Sources

  • CVE.orgVulnerability recordCVE-2026-112908

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-112908

    30-day exploitation probability 0.12%

    first.org
  • GitHub Advisory DatabasePackage advisoryGHSA-6627-m3xw-93mp

    filelock: StrictSoftFileLock creates its claim directories without the lock mode, so another local user with a write bit on them can end a live hold

    github.com
  • GitLab Advisory DatabasePackage advisoryCVE-2026-112908

    StrictSoftFileLock and AsyncStrictSoftFileLock apply the caller's mode to the sentinel (the lock file at ) and to both claim files (the files whose presence says a process wants or holds the lock). They create the two directories that hold the claims, .filelock and .filelock/claims, with a bare mkdir(). That gives 0o777 filtered through the umask (a per-process mask that removes permission bits fr

    advisories.gitlab.com
  • Red Hat Security DataVendor advisoryCVE-2026-112908

    filelock: filelock: unauthorized concurrent access via insecure claim directory permissions

    access.redhat.com

References

Freshness

Last verified in this catalog Nov 6, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • Red Hat Security DataNov 7, 2026
  • FIRST EPSSNov 6, 2026
  • GitLab Advisory DatabaseOct 30, 2026
  • CVE.orgOct 29, 2026
  • GitHub Advisory DatabaseOct 29, 2026