{"id":"CVE-2026-54906","aliases":["GHSA-6wx8-w4f5-wwcr"],"url":"https://o3.security/vulnerability/CVE-2026-54906","summary":"concurrent-ruby: ReadWriteLock allows wrong-thread write release and stray read-release counter corruption","details":"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.","published":"2026-06-24T15:46:01.116Z","modified":"2026-07-15T01:49:01.496327527Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"RubyGems","name":"concurrent-ruby","fixedVersion":"1.3.7"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54906.json"},{"type":"ADVISORY","url":"https://github.com/ruby-concurrency/concurrent-ruby/security/advisories/GHSA-6wx8-w4f5-wwcr"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-54906"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-15T01:49:01.496327527Z"}}