concurrent-ruby is a modern concurrency tools for Ruby. Prior to 1.3.7, Concurrent::ReadWriteLock#release_write_lock does not verify that the calling thread acquired the write lock. Any thread with access to the lock object can release an active write lock held by another thread. A second writer can then enter its critical section while the first writer is still running. Concurrent::ReadWriteLock#release_read_lock also decrements the shared counter even when no read lock is held. Calling it on a fresh lock changes the counter from 0 to -1, after which normal read acquisition raises Concurrent::ResourceLimitError. This is a synchronization correctness issue in the public Concurrent::ReadWriteLock API. This vulnerability is fixed in 1.3.7.
History

Wed, 24 Jun 2026 18:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Wed, 24 Jun 2026 16:30:00 +0000

Type Values Removed Values Added
Description concurrent-ruby is a modern concurrency tools for Ruby. Prior to 1.3.7, Concurrent::ReadWriteLock#release_write_lock does not verify that the calling thread acquired the write lock. Any thread with access to the lock object can release an active write lock held by another thread. A second writer can then enter its critical section while the first writer is still running. Concurrent::ReadWriteLock#release_read_lock also decrements the shared counter even when no read lock is held. Calling it on a fresh lock changes the counter from 0 to -1, after which normal read acquisition raises Concurrent::ResourceLimitError. This is a synchronization correctness issue in the public Concurrent::ReadWriteLock API. This vulnerability is fixed in 1.3.7.
Title concurrent-ruby: ReadWriteLock allows wrong-thread write release and stray read-release counter corruption
Weaknesses CWE-414
CWE-667
References
Metrics cvssV4_0

{'score': 2.1, 'vector': 'CVSS:4.0/AV:L/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-06-24T17:57:07.650Z

Reserved: 2026-06-16T13:49:33.556Z

Link: CVE-2026-54906

cve-icon Vulnrichment

Updated: 2026-06-24T17:57:02.851Z

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-06-24T17:30:16Z