CVE-2026-54905

CVE-2026-54905 affects the concurrent-ruby library, specifically Concurrent::ReentrantReadWriteLock. Before version 1.3.7, after a thread acquires the read lock 32,768 times, the local read count overflows into the WRITE_LOCK_HELD bit, causing try_write_lock to treat the thread as if it holds a w...

GHSA-6WX8-W4F5-WWCR Concurrent Ruby: ReadWriteLock allows wrong-thread write release and stray read-release counter corruption

Summary Concurrent::ReadWriteLockreleasewritelock 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...

Concurrent Ruby: ReadWriteLock allows wrong-thread write release and stray read-release counter corruption

Summary Concurrent::ReadWriteLockreleasewritelock 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...

Improper Locking

Overview Affected versions of this package are vulnerable to Improper Locking in the releasewritelock and releasereadlock functions. An attacker can disrupt synchronization guarantees and exploit data races or cause denial of service by invoking these functions from unauthorized threads or withou...

GHSA-WV3X-4VXV-WHPP Concurrent Ruby: `ReentrantReadWriteLock` read-count overflow grants a write lock without exclusivity

Summary Concurrent::ReentrantReadWriteLock can incorrectly grant a write lock after one thread acquires the read lock 32,768 times. The lock stores a thread's local read and write hold counts in one integer. The low 15 bits are used for the read hold count, and bit 15 is used as WRITELOCKHELD...

Concurrent Ruby: `ReentrantReadWriteLock` read-count overflow grants a write lock without exclusivity

Summary Concurrent::ReentrantReadWriteLock can incorrectly grant a write lock after one thread acquires the read lock 32,768 times. The lock stores a thread's local read and write hold counts in one integer. The low 15 bits are used for the read hold count, and bit 15 is used as WRITELOCKHELD...

Wrap-around Error

Overview Affected versions of this package are vulnerable to Wrap-around Error in ReentrantReadWriteLock that causes incorrect write locks. An attacker can cause a thread to incorrectly obtain a write lock without exclusivity by repeatedly acquiring the read lock 32,768 times, which overflows the...

Infinite loop

Overview Affected versions of this package are vulnerable to Infinite loop in the AtomicReferenceupdate function when the current value is Float::NAN. An attacker can cause indefinite busy retry loops and CPU exhaustion by supplying malicious numeric data. Remediation Upgrade concurrent-ruby to...

PT-2026-51091

Name of the Vulnerable Software and Affected Versions concurrent-ruby versions prior to 1.3.7 Description Concurrent::ReentrantReadWriteLock can incorrectly grant a write lock after a single thread acquires the read lock 32,768 times. The lock manages a thread's local read and write hold counts...

Concurrent Ruby - `AtomicReference#update` livelocks when the stored value is `Float::NAN`

Summary Concurrent::AtomicReferenceupdate can enter a permanent busy retry loop when the current value is Float::NAN. The issue is caused by the interaction between: - AtomicReferenceupdate, which retries until compareandsetoldvalue, newvalue succeeds. - Numeric compareandset, which checks old ==...

Malicious Package

Overview concurrent-ruby is a malicious package. This package contains malicious code, and its content was removed from the official package manager. While this package might be attempting to impersonate a valid organization, there is no connection between that organization and this package...

EUVD-2025-32980

Malicious code in concurrent-ruby npm...

Malicious code in concurrent-ruby (npm)

--- -= Per source details. Do not edit below this line.=- Source: ghsa-malware 3a9a44087853b6fa03aa9a4f09e51ff827a6d90b6fe4da7c38cc6ef2764ad99d Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be...

MAL-2025-48026 Malicious code in concurrent-ruby (npm)

--- -= Per source details. Do not edit below this line.=- Source: ghsa-malware 3a9a44087853b6fa03aa9a4f09e51ff827a6d90b6fe4da7c38cc6ef2764ad99d Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be...