CVE-2026-54906 (GCVE-0-2026-54906)
Vulnerability from cvelistv5 – Published: 2026-06-24 15:46 – Updated: 2026-06-24 17:57
VLAI
EPSS
VEX
Title
concurrent-ruby: ReadWriteLock allows wrong-thread write release and stray read-release counter corruption
Summary
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.
Severity
SSVC
Exploitation: poc
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-06-24 17:56 UTC
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://github.com/ruby-concurrency/concurrent-ru… | x_refsource_CONFIRM |
Impacted products
1 product
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| ruby-concurrency | concurrent-ruby |
Affected:
< 1.3.7
|
guessed |
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