filelock: SoftReadWriteLock follows a lock tree swapped in after its first acquire and writes lock records into directories of the user running the lock

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

filelock is a platform-independent file lock for Python. From 4.1.0 until 4.2.1, SoftReadWriteLock and AsyncSoftReadWriteLock cache a successful check of the <path>.rw lock tree and resolve its names again during later record operations, allowing another local user who can replace that tree after the first acquisition to redirect lock-record writes into directories writable by the lock user. This issue is fixed in version 4.2.1.

Source published

20 Oct 2026 14:43:18 UTC

Source modified

28 Oct 2026 14:14:54 UTC

Observed here

28 Oct 2026 15:46:50 UTC

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CVSS 3.1 · 3.3 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N