{"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": "2026-06-25T13:20:00.135Z"}, "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"}}, "adp": [{"references": [{"url": "https://github.com/ruby-concurrency/concurrent-ruby/security/advisories/GHSA-h8w8-99g7-qmvj", "tags": ["exploit"]}], "metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-06-25T13:19:55.812897Z", "id": "CVE-2026-54904", "options": [{"Exploitation": "poc"}, {"Automatable": "no"}, {"Technical Impact": "partial"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-06-25T13:20:00.135Z"}}]}}

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{"bugzilla": {"description": "concurrent-ruby: rubygem-concurrent-ruby: concurrent-ruby: Denial of Service due to infinite loop in AtomicReference#update", "id": "2492250", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2492250"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.9", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-835", "details": ["A flaw was found in concurrent-ruby. A remote attacker could exploit a vulnerability in the Concurrent::AtomicReference#update method, which can enter a permanent busy retry loop. This occurs when the current value is a special 'Not a Number' (Float::NAN) floating-point value, causing the method to repeatedly attempt an operation without success. This can lead to a Denial of Service (DoS), where the affected application experiences CPU exhaustion or becomes unresponsive."], "mitigation": {"lang": "en:us", "value": "The vulnerable `AtomicReference#update` code path is not exercised with externally-derived numeric values, making exploitation not possible in this context. \nUpdating to concurrent-ruby 1.3.7 when available in upstream dependencies will fully resolve this issue."}, "name": "CVE-2026-54904", "package_state": [{"cpe": "cpe:/a:redhat:red_hat_3scale_amp:2", "fix_state": "Not affected", "package_name": "3scale-amp21/backend", "product_name": "Red Hat 3scale API Management Platform 2"}, {"cpe": "cpe:/a:redhat:red_hat_3scale_amp:2", "fix_state": "Not affected", "package_name": "3scale-amp21/system", "product_name": "Red Hat 3scale API Management Platform 2"}, {"cpe": "cpe:/a:redhat:red_hat_3scale_amp:2", "fix_state": "Not affected", "package_name": "3scale-amp21/zync", "product_name": "Red Hat 3scale API Management Platform 2"}, {"cpe": "cpe:/a:redhat:red_hat_3scale_amp:2", "fix_state": "Not affected", "package_name": "3scale-amp22/backend", "product_name": "Red Hat 3scale API Management Platform 2"}, {"cpe": "cpe:/a:redhat:red_hat_3scale_amp:2", "fix_state": "Not affected", "package_name": "3scale-amp22/system", "product_name": "Red Hat 3scale API Management Platform 2"}, {"cpe": "cpe:/a:redhat:red_hat_3scale_amp:2", "fix_state": "Not affected", "package_name": "3scale-amp22/zync", "product_name": "Red Hat 3scale API Management Platform 2"}, {"cpe": "cpe:/a:redhat:red_hat_3scale_amp:2", "fix_state": "Not affected", "package_name": "3scale-amp26/toolbox", "product_name": "Red Hat 3scale API Management Platform 2"}, {"cpe": "cpe:/a:redhat:red_hat_3scale_amp:2", "fix_state": "Not affected", "package_name": "3scale-amp2/backend-rhel8", "product_name": "Red Hat 3scale API Management Platform 2"}, {"cpe": "cpe:/a:redhat:red_hat_3scale_amp:2", "fix_state": "Not affected", "package_name": "3scale-amp2/system-rhel7", "product_name": "Red Hat 3scale API Management Platform 2"}, {"cpe": "cpe:/a:redhat:red_hat_3scale_amp:2", "fix_state": "Not affected", "package_name": "3scale-amp2/system-rhel8", "product_name": "Red Hat 3scale API Management Platform 2"}, {"cpe": "cpe:/a:redhat:red_hat_3scale_amp:2", "fix_state": "Not affected", "package_name": "3scale-amp2/system-rhel9", "product_name": "Red Hat 3scale API Management Platform 2"}, {"cpe": "cpe:/a:redhat:red_hat_3scale_amp:2", "fix_state": "Not affected", "package_name": "3scale-amp2/toolbox-rhel8", "product_name": "Red Hat 3scale API Management Platform 2"}, {"cpe": "cpe:/a:redhat:red_hat_3scale_amp:2", "fix_state": "Not affected", "package_name": "3scale-amp2/toolbox-rhel9", "product_name": "Red Hat 3scale API Management Platform 2"}, {"cpe": "cpe:/a:redhat:red_hat_3scale_amp:2", "fix_state": "Not affected", "package_name": "3scale-amp2/zync-rhel8", "product_name": "Red Hat 3scale API Management Platform 2"}, {"cpe": "cpe:/a:redhat:red_hat_3scale_amp:2", "fix_state": "Not affected", "package_name": "3scale-amp2/zync-rhel9", "product_name": "Red Hat 3scale API Management Platform 2"}, {"cpe": "cpe:/a:redhat:openstack:17.1", "fix_state": "Not affected", "package_name": "rubygem-concurrent-ruby", "product_name": "Red Hat OpenStack Platform 17.1"}, {"cpe": "cpe:/a:redhat:satellite:6", "fix_state": "Not affected", "package_name": "rubygem-concurrent-ruby", "product_name": "Red Hat Satellite 6"}, {"cpe": "cpe:/a:redhat:satellite:6", "fix_state": "Not affected", "package_name": "satellite:el8/rubygem-concurrent-ruby", "product_name": "Red Hat Satellite 6"}], "public_date": "2026-06-24T15:44:21Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-54904\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-54904\nhttps://github.com/ruby-concurrency/concurrent-ruby/security/advisories/GHSA-h8w8-99g7-qmvj"], "statement": "The issue arises when the `AtomicReference#update` method encounters a `Float::NAN` value, leading to an infinite retry loop and potential CPU exhaustion. The vulnerable `AtomicReference#update` method is not used with externally-controlled (e.g: `Float::NAN`) values - thus exploitation is not possible.", "threat_severity": "Moderate"}

{"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"]}