concurrent-ruby: `ReentrantReadWriteLock` read-count overflow grants a write lock without exclusivity_CVE-2026-54905

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    "description": "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.",
    "published": "2026-06-24T15:42:44.257Z",
    "modified": "2026-06-24T16:41:34.224Z",
    "type": "cve",
    "title": "concurrent-ruby:  `ReentrantReadWriteLock` read-count overflow grants a write lock without exclusivity",
    "source": "GitHub_M",
    "references": "https://github.com/ruby-concurrency/concurrent-ruby/security/advisories/GHSA-wv3x-4vxv-whpp",
    "id": "CVE-2026-54905",
    "bulletinFamily": "",
    "cwe": [
        "CWE-128"
    ],
    "cvelist": null,
    "sourceData": "ruby-concurrency concurrent-ruby < 1.3.7",
    "sourceHref": "",
    "cvss": {
        "score": 2,
        "severity": "LOW",
        "vector": "CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N",
        "version": "4.0"
    },
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    "href": "",
    "category_name": "CVE",
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    "product": "concurrent-ruby",
    "version": "< 1.3.7",
    "vendor": "ruby-concurrency",
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