{"items":[{"id":"NVI-00016079","kind":"vulnerability","title":"Concurrent Ruby: `ReentrantReadWriteLock` read-count overflow grants a write lock without exclusivity","revision":2,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected.","NVD lastModified does not establish freshness of every associated CPE record."],"lifecycle":"active","identifiers":["GHSA-wv3x-4vxv-whpp","CVE-2026-54905"],"plain_summary":"GitHub lists this reviewed advisory for concurrent-ruby. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.","review_status":"source_listed","control_topics":[],"public_actions":[{"summary":"Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.","source_ids":["sr-036c417dd35dd6d80e422fefd5c939a7"],"action_type":"investigate","limitations":"Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system.","current_supported_target":null}],"schema_version":"1.1.0","source_metrics":[{"kind":"CVSS","as_of":"2026-07-20T13:37:00.000Z","value":"5.5 low","meaning":"GitHub source severity; exploitability and local consequence require separate evidence.","source_id":"sr-1a04f42e8debcd6abbbb24089f8ade87"},{"kind":"CVSS","as_of":"2026-10-25T22:10:00.150Z","value":"5.5 MEDIUM (3.1)","meaning":"nvd@nist.gov severity; no combined Null risk score.","source_id":"sr-036c417dd35dd6d80e422fefd5c939a7"},{"kind":"CVSS","as_of":"2026-10-25T22:10:00.150Z","value":"2 LOW (4.0)","meaning":"security-advisories@github.com severity; no combined Null risk score.","source_id":"sr-036c417dd35dd6d80e422fefd5c939a7"}],"why_it_matters":"Published affected context helps an owner decide what evidence to gather. This report has not examined your application.","related_sources":[{"id":"sr-1a04f42e8debcd6abbbb24089f8ade87","url":"https://github.com/advisories/GHSA-wv3x-4vxv-whpp","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-wv3x-4vxv-whpp","publisher":"GitHub Advisory Database","observed_at":"2026-11-04T02:49:06.528Z"},{"id":"sr-036c417dd35dd6d80e422fefd5c939a7","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-54905","basis":"official_catalog","notes":"This product uses data from the NVD API but is not endorsed or certified by the NVD.","title":"CVE-2026-54905","publisher":"NIST National Vulnerability Database","observed_at":"2026-11-08T01:48:19.229Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-1a04f42e8debcd6abbbb24089f8ade87"],"technology":"concurrent-ruby","known_exclusions":[],"conditions_summary":"### Summary\n`Concurrent::ReentrantReadWriteLock` can incorrectly grant a write lock after one thread acquires the read lock 32,768 times.\n\nThe 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.\n\nThis 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.\n\n### Version\nSoftware: concurrent-ruby\nVersion: 1.3.6\nCommit: 7a1b78941c081106c20a9ca0144ac73a48d254ab\n\n### Details\n\nThe implementation uses a shared counter to track global readers/writers and a per-thread local counter to support reentrancy:\n\n```ruby\nREADER_BITS    = 15\nWRITER_BITS    = 14\n\nWAITING_WRITER = 1 << READER_BITS\nRUNNING_WRITER = 1 << (READER_BITS + WRITER_BITS)\nMAX_READERS    = WAITING_WRITER - 1\nMAX_WRITERS    = RUNNING_WRITER - MAX_READERS - 1\n\nWRITE_LOCK_HELD = 1 << READER_","public_affected_ranges":["< 1.3.7"]}],"null_published_at":"2026-11-08T19:53:44.016Z","source_updated_at":"2026-07-20T13:37:00.000Z","source_disclosed_at":"2026-06-19T20:47:38.000Z","is_synthetic_fixture":false,"null_last_reviewed_at":null,"public_change_summary":"Source facts changed; compare the preserved prior revision.","null_first_observed_at":"2026-11-04T02:49:06.528Z"},{"id":"NVI-00016079","kind":"vulnerability","title":"Concurrent Ruby: `ReentrantReadWriteLock` read-count overflow grants a write lock without exclusivity","revision":1,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-wv3x-4vxv-whpp","CVE-2026-54905"],"plain_summary":"GitHub lists this reviewed advisory for concurrent-ruby. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.","review_status":"source_listed","control_topics":[],"public_actions":[{"summary":"Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.","source_ids":["sr-1a04f42e8debcd6abbbb24089f8ade87"],"action_type":"investigate","limitations":"Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system.","current_supported_target":null}],"schema_version":"1.1.0","source_metrics":[{"kind":"CVSS","as_of":"2026-07-20T13:37:00.000Z","value":"5.5 low","meaning":"GitHub source severity; exploitability and local consequence require separate evidence.","source_id":"sr-1a04f42e8debcd6abbbb24089f8ade87"}],"why_it_matters":"Published affected context helps an owner decide what evidence to gather. This report has not examined your application.","related_sources":[{"id":"sr-1a04f42e8debcd6abbbb24089f8ade87","url":"https://github.com/advisories/GHSA-wv3x-4vxv-whpp","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-wv3x-4vxv-whpp","publisher":"GitHub Advisory Database","observed_at":"2026-11-04T02:49:06.528Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-1a04f42e8debcd6abbbb24089f8ade87"],"technology":"concurrent-ruby","known_exclusions":[],"conditions_summary":"### Summary\n`Concurrent::ReentrantReadWriteLock` can incorrectly grant a write lock after one thread acquires the read lock 32,768 times.\n\nThe 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.\n\nThis 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.\n\n### Version\nSoftware: concurrent-ruby\nVersion: 1.3.6\nCommit: 7a1b78941c081106c20a9ca0144ac73a48d254ab\n\n### Details\n\nThe implementation uses a shared counter to track global readers/writers and a per-thread local counter to support reentrancy:\n\n```ruby\nREADER_BITS    = 15\nWRITER_BITS    = 14\n\nWAITING_WRITER = 1 << READER_BITS\nRUNNING_WRITER = 1 << (READER_BITS + WRITER_BITS)\nMAX_READERS    = WAITING_WRITER - 1\nMAX_WRITERS    = RUNNING_WRITER - MAX_READERS - 1\n\nWRITE_LOCK_HELD = 1 << READER_","public_affected_ranges":["< 1.3.7"]}],"null_published_at":"2026-11-04T10:04:27.880Z","source_updated_at":"2026-07-20T13:37:00.000Z","source_disclosed_at":"2026-06-19T20:47:38.000Z","is_synthetic_fixture":false,"null_last_reviewed_at":null,"public_change_summary":"First indexed by Null; source disclosure date is shown separately.","null_first_observed_at":"2026-11-04T02:49:06.528Z"}],"next_cursor":null,"snapshot_revision":"42594"}