{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-54904", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-06-16T13:49:33.556Z", "datePublished": "2026-06-24T15:44:21.992Z", "dateUpdated": "2026-06-24T15:44:21.992Z"}, "containers": {"cna": {"title": "concurrent-ruby: `AtomicReference#update` livelocks when the stored value is `Float::NAN`", "problemTypes": [{"descriptions": [{"cweId": "CWE-835", "lang": "en", "description": "CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop')", "type": "CWE"}]}], "metrics": [{"cvssV4_0": {"attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "baseScore": 8.2, "baseSeverity": "HIGH", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N", "version": "4.0"}}], "references": [{"name": "https://github.com/ruby-concurrency/concurrent-ruby/security/advisories/GHSA-h8w8-99g7-qmvj", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/ruby-concurrency/concurrent-ruby/security/advisories/GHSA-h8w8-99g7-qmvj"}], "affected": [{"vendor": "ruby-concurrency", "product": "concurrent-ruby", "versions": [{"version": "< 1.3.7", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-06-24T15:44:21.992Z"}, "descriptions": [{"lang": "en", "value": "concurrent-ruby is a modern concurrency tools for Ruby. Prior to 1.3.7, Concurrent::AtomicReference#update can enter a permanent busy retry loop when the current value is Float::NAN. The issue is caused by the interaction between AtomicReference#update, which retries until compare_and_set(old_value, new_value) succeeds; Numeric compare_and_set, which checks old == old_value before attempting the underlying atomic swap.; and Ruby NaN semantics, where Float::NAN == Float::NAN is always false. As a result, once an AtomicReference contains Float::NAN, calling #update repeatedly evaluates the caller's block and never returns. In services that store externally derived numeric values in an AtomicReference, this can cause CPU exhaustion or permanent request/job hangs. This vulnerability is fixed in 1.3.7."}], "source": {"advisory": "GHSA-h8w8-99g7-qmvj", "discovery": "UNKNOWN"}}}}

{}

{}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,1.3.7)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "cna", "scores": [{"score": 100.0, "source": "cna"}]}, "original": {"product": "concurrent-ruby", "source": "cna", "vendor": "ruby-concurrency"}, "product": "concurrent-ruby", "vendor": "ruby-concurrency"}], "created": "2026-06-24T17:30:16.930180+00:00", "updated": "2026-06-24T20:40:40.969719+00:00", "vendors": ["ruby-concurrency", "ruby-concurrency$PRODUCT$concurrent-ruby"]}