Vulnerability 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.
CVSS Score
CRITICAL
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Rubyconcurrency | Concurrent Ruby | < 1.3.7 |
Related Weaknesses (CWE)
References
- https://github.com/ruby-concurrency/concurrent-ruby/security/advisories/GHSA-6wxThird Party Advisory
- https://github.com/ruby-concurrency/concurrent-ruby/security/advisories/GHSA-6wxThird Party Advisory
FAQ
What is CVE-2026-54906?
CVE-2026-54906 is a vulnerability with a CVSS score of 9.8 (CRITICAL). 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 ac...
How severe is CVE-2026-54906?
CVE-2026-54906 has been rated CRITICAL with a CVSS base score of 9.8/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-54906?
Check the references section above for vendor advisories and patch information. Affected products include: Rubyconcurrency Concurrent Ruby.