CVE-2026-54905

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{"affected": [{"affectedData": [{"product": "concurrent-ruby", "vendor": "ruby-concurrency", "versions": [{"status": "affected", "version": "< 1.3.7"}]}], "source": "security-advisories@github.com"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:rubyconcurrency:concurrent_ruby:*:*:*:*:*:ruby:*:*", "matchCriteriaId": "4BBFFB42-BEF4-4DF8-BAB8-4B728A8CA930", "versionEndExcluding": "1.3.7", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "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."}, {"lang": "es", "value": "concurrent-ruby es una herramienta moderna de concurrencia para Ruby. Antes de 1.3.7, Concurrent::ReentrantReadWriteLock puede conceder incorrectamente un bloqueo de escritura despu\u00e9s de que un hilo adquiera el bloqueo de lectura 32.768 veces. El bloqueo almacena los recuentos locales de retenci\u00f3n de lectura y escritura de un hilo en un solo entero. Los 15 bits inferiores se utilizan para el recuento de retenci\u00f3n de lectura, y el bit 15 se utiliza como WRITE_LOCK_HELD. Despu\u00e9s de 32.768 adquisiciones de lectura reentrantes, el recuento de lectura local se superpone con el bit de bloqueo de escritura. try_write_lock entonces trata al hilo como si ya tuviera un bloqueo de escritura y devuelve verdadero sin establecer el bit global RUNNING_WRITER. Esto rompe la garant\u00eda fundamental de exclusi\u00f3n mutua: al llamador se le dice que tiene un bloqueo de escritura, pero otros hilos a\u00fan pueden mantener o adquirir bloqueos de lectura al mismo tiempo. Esta vulnerabilidad se corrige en 1.3.7."}], "id": "CVE-2026-54905", "lastModified": "2026-10-25T22:10:00.150", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "NONE", "baseScore": 5.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 3.6, "source": "nvd@nist.gov", "type": "Primary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "attackVector": "LOCAL", "availabilityRequirement": "NOT_DEFINED", "baseScore": 2.0, "baseSeverity": "LOW", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "privilegesRequired": "LOW", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "version": "4.0", "vulnAvailabilityImpact": "LOW", "vulnConfidentialityImpact": "LOW", "vulnIntegrityImpact": "LOW", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "security-advisories@github.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-54905", "options": [{"exploitation": "poc"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-06-24T16:41:31.221708Z", "version": "2.0.3"}}]}, "published": "2026-06-24T17:17:29.403", "references": [{"source": "security-advisories@github.com", "tags": ["Third Party Advisory"], "url": "https://github.com/ruby-concurrency/concurrent-ruby/security/advisories/GHSA-wv3x-4vxv-whpp"}, {"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "tags": ["Third Party Advisory"], "url": "https://github.com/ruby-concurrency/concurrent-ruby/security/advisories/GHSA-wv3x-4vxv-whpp"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-128"}], "source": "security-advisories@github.com", "type": "Primary"}]}

{"bugzilla": {"description": "concurrent-ruby: Concurrent-ruby: Incorrect write lock granting leading to broken mutual exclusion", "id": "2492251", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2492251"}, "csaw": false, "cvss3": {"cvss3_base_score": "4.7", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N", "status": "draft"}, "cwe": "CWE-190", "details": ["A flaw was found in concurrent-ruby. The Concurrent::ReentrantReadWriteLock component can incorrectly grant a write lock to a thread while other threads still hold or can acquire read locks. This occurs when a thread acquires a read lock 32,768 times, causing an internal counter to incorrectly indicate a write lock is held. This breaks the fundamental mutual-exclusion guarantee of the lock, potentially leading to unexpected behavior or data corruption due to concurrent access."], "mitigation": {"lang": "en:us", "value": "Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability."}, "name": "CVE-2026-54905", "package_state": [{"cpe": "cpe:/a:redhat:red_hat_3scale_amp:2", "fix_state": "Fix deferred", "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": "Fix deferred", "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": "Fix deferred", "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": "Fix deferred", "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": "Fix deferred", "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": "Fix deferred", "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": "Fix deferred", "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": "Fix deferred", "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": "Fix deferred", "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": "Fix deferred", "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": "Fix deferred", "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": "Fix deferred", "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": "Fix deferred", "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": "Fix deferred", "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": "Fix deferred", "package_name": "3scale-amp2/zync-rhel9", "product_name": "Red Hat 3scale API Management Platform 2"}, {"cpe": "cpe:/a:redhat:openstack:17.1", "fix_state": "Fix deferred", "package_name": "rubygem-concurrent-ruby", "product_name": "Red Hat OpenStack Platform 17.1"}, {"cpe": "cpe:/a:redhat:satellite:6", "fix_state": "Fix deferred", "package_name": "rubygem-concurrent-ruby", "product_name": "Red Hat Satellite 6"}, {"cpe": "cpe:/a:redhat:satellite:6", "fix_state": "Fix deferred", "package_name": "satellite-capsule:el8/rubygem-concurrent-ruby", "product_name": "Red Hat Satellite 6"}], "public_date": "2026-06-24T15:42:44Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-54905\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-54905\nhttps://github.com/ruby-concurrency/concurrent-ruby/security/advisories/GHSA-wv3x-4vxv-whpp"], "statement": "Red Hat rates this flaw as Low impact, consistent with the upstream CVEORG assessment (2.0). The vulnerability requires a single thread to acquire the same ReentrantReadWriteLock read lock 32,768 times reentrantly before the internal counter overflows into the write-lock bit. This precondition does not arise in normal application usage. While concurrent-ruby ships the vulnerable lock class in Red Hat products, no transitive dependency was confirmed to instantiate ReentrantReadWriteLock.", "threat_severity": "Low"}

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