What is CVE-2026-54906?

CVE-2026-54906 is a critical-severity vulnerability in Ruby-concurrency Concurrent-ruby, classified under CWE-414. CVSS score: 9.8/10. Published 2026-06-24.

How severe is CVE-2026-54906?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Vulnerability in Ruby-concurrency Concurrent-ruby

CVE-2026-54906

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…

EPSS: 0.002 (5.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Ruby-concurrency Concurrent-ruby — versions < 1.3.7
Rubyconcurrency Concurrent_ruby

Weakness classification (CWE)

References

security-advisories@github.com (x_refsource_CONFIRM, Third Party Advisory)

Frequently asked questions

What is CVE-2026-54906?: CVE-2026-54906 is a critical-severity vulnerability in Ruby-concurrency Concurrent-ruby, classified under CWE-414. CVSS score: 9.8/10. Published 2026-06-24.
How severe is CVE-2026-54906?: Critical severity. CVSS v3 base score is 9.8 out of 10.