CVE-2026-54905

concurrent-ruby is a modern concurrency tools for Ruby. Prior to 1.3.7, 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 WRITE_LOCK_HELD. After 32,768 reentrant read acquisitions, the local read count crosses into the write-lock bit. try_write_lock then treats the thread as already holding a write lock and returns true without setting the global RUNNING_WRITER bit. This breaks the core mutual-exclusion guarantee: the caller is told it has a write lock, but other threads can still hold or acquire read locks at the same time. This vulnerability is fixed in 1.3.7.

CVSS v3 5.5 MEDIUM

5.5^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 1.8 / Impact : 3.6

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact NONE

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/ruby-concurrency/concurrent-ruby/security/advisories/GHSA-wv3x-4vxv-whpp	Third Party Advisory
https://github.com/ruby-concurrency/concurrent-ruby/security/advisories/GHSA-wv3x-4vxv-whpp	Third Party Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:rubyconcurrency:concurrent_ruby:*:*:*:*:*:ruby:*:*

History

No history.

Information

Published : 2026-06-24 17:17

Updated : 2026-06-26 20:01

NVD link : CVE-2026-54905

Mitre link : CVE-2026-54905

CVE.ORG link : CVE-2026-54905

JSON object : View

Products Affected

rubyconcurrency

concurrent_ruby

CWE

CWE-128

Wrap-around Error

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