Critical
ruby-concurrent — security advisory
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.
- Products
- ruby-concurrent
- Affected versions
- 1.0.0-1, 1.0.5-1, 1.0.5-3, 1.0.5-4, 1.1.6+dfsg-2, 1.1.6+dfsg-3, 1.1.6+dfsg-3build1, 1.1.6+dfsg-4, 1.1.6+dfsg-5build2, 1.1.6+dfsg-5build3, 1.2.3-2build1, 1.3.4-1, 1.3.6-1, 1.3.7-4, 1.3.8-1
- Fixed versions
- Not specified
- CVEs
- CVE-2026-54906
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 03:08 UTC · Revision 1
Source evidence
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.
osv:UBUNTU-CVE-2026-54906
ruby-concurrent
Fixed versions: Not specified
ruby-concurrent
Fixed versions: Not specified
ruby-concurrent
Fixed versions: Not specified
ruby-concurrent
Fixed versions: Not specified
ruby-concurrent
Fixed versions: Not specified
ruby-concurrent
Fixed versions: Not specified
ruby-concurrent
Fixed versions: Not specified
ruby-concurrent
Fixed versions: Not specified
Complete source record
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