{
  "cveId": "CVE-2026-54906",
  "url": "https://patchblox.com/security/cve/CVE-2026-54906",
  "summary": "CVE-2026-54906 is fixed in ruby-concurrent on 1 platform by DEBIAN-CVE-2026-54906 (version 1.3.7-1), released July 3, 2026. It is not reported as exploited. Patch Radar priority: High.",
  "title": "concurrent-ruby: ReadWriteLock allows wrong-thread write release and stray read-release counter corruption",
  "description": "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.",
  "published": "2026-06-24T17:17:29Z",
  "severity": "Low",
  "cvss": 9.8,
  "cvssVector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
  "cwe": "Missing Lock Check",
  "epss": 0.0016,
  "epssPercentile": 0.05248,
  "priority": "High",
  "priorityTier": 3,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "vendorAdvisory": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-54906",
  "fixes": [
    {
      "platform": "linux",
      "product": "ruby-concurrent",
      "release": "Debian 14",
      "fixedVersion": "1.3.7-1",
      "fix": "DEBIAN-CVE-2026-54906",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-54906",
      "released": "2026-07-03T14:54:39Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-09T01:18:40Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}