CVE-2026-54904

A flaw was found in concurrent-ruby. A remote attacker could exploit a vulnerability in the Concurrent::AtomicReferenceupdate method, which can enter a permanent busy retry loop. This occurs when the current value is a special 'Not a Number' Float::NAN floating-point value, causing the method to...

CVE-2026-54904 concurrent-ruby: `AtomicReference#update` livelocks when the stored value is `Float::NAN`

concurrent-ruby is a modern concurrency tools for Ruby. Prior to 1.3.7, 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,...

CVE-2026-54904 concurrent-ruby: `AtomicReference#update` livelocks when the stored value is `Float::NAN`

concurrent-ruby is a modern concurrency tools for Ruby. Prior to 1.3.7, 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,...

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...