CVE catalog

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 ac

[CVE catalog]

Severity
Low · CVSS 3.6CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:L
Published
Source
[NVD] · [CVE record]
EPSS
0.16% · Oct 25, 2026

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.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

DistributionPackageReleaseVersionStatus
Debianruby-concurrentsid1.3.8-1fixed
Debianruby-concurrentforky1.3.8-1fixed
Debianruby-concurrenttrixie1.3.5-1vulnerable
Debianruby-concurrentbookworm1.1.6+dfsg-5vulnerable
Cperuby-concurrentNot reportedNot reportedvulnerable
Cpeconcurrent_rubyNot reported1.3.7fixed
Cpeconcurrent_rubyNot reported1.3.7fixed

Fixed-version evidence

DistributionPackageTypeReleaseFixed versionUrgencyOriginBugs
Debianruby-concurrentsourcesid1.3.7-1not yet assignedNot reportedNot reported
Debianruby-concurrentsourceforky1.3.7-1not yet assignedNot reportedNot reported
Debianruby-concurrentsourcetrixie(unfixed)not yet assignedNot reportedNot reported
Debianruby-concurrentsourcebookworm(unfixed)not yet assignedNot reportedNot reported
Cpeconcurrent_rubycpeNot reported1.3.7Not reportedNot reportedNot reported
Cpeconcurrent_rubycpeNot reported1.3.7Not reportedNVD-CVE-2026-54906Not reported

Notes

[trixie] ruby-concurrent: Minor issue [bookworm] ruby-concurrent: Minor issue; requires an application to release a ReadWriteLock it does not hold via the manual acquire_*/release_* API, and the upstream fix changes release_read_lock/release_write_lock to raise IllegalOperationError

OpenFactory catalog packages

[Debian 12 (Bookworm)]

  • [ruby-concurrent]Affected
    Details (2)

    • 1.1.6+dfsg-5 · all · bookworm

      Affected

      nvd · ruby-concurrent · debian · bookworm; nvd · ruby-concurrent · debian · 12

    • 1.1.6+dfsg-5 · all · bookworm

      Affected

      nvd · ruby-concurrent · debian · bookworm; nvd · ruby-concurrent · debian · 12

  • [ruby-concurrent-ext]Affected

    Source package: [ruby-concurrent]

    Details (2)

    • 1.1.6+dfsg-5+b2 · amd64 · bookworm

      Affected

      nvd · ruby-concurrent · debian · bookworm; nvd · ruby-concurrent · debian · 12

    • 1.1.6+dfsg-5+b2 · arm64 · bookworm

      Affected

      nvd · ruby-concurrent · debian · bookworm; nvd · ruby-concurrent · debian · 12

[Debian 13 (Trixie)]

  • [ruby-concurrent]Affected
    Details (2)

    • 1.3.5-1 · all · trixie

      Affected

      nvd · ruby-concurrent · debian · 13

    • 1.3.5-1 · all · trixie

      Affected

      nvd · ruby-concurrent · debian · 13

  • [ruby-concurrent-ext]Affected

    Source package: [ruby-concurrent]

    Details (2)

    • 1.3.5-1 · amd64 · trixie

      Affected

      nvd · ruby-concurrent · debian · 13

    • 1.3.5-1 · arm64 · trixie

      Affected

      nvd · ruby-concurrent · debian · 13

Observed:

References

[Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]