CVE-2026-42256

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From versions 0.4.0 to before 0.4.24, 0.5.0 to before 0.5.14, and 0.6.0 to before 0.6.4, when authenticating a connection with SCRAM-SHA1 or SCRAM-SHA256, a hostile server can perform a computational denial-of-service attack on the client process by sending a big iteration count value. This issue has been patched in versions 0.4.24, 0.5.14, and 0.6.4."}, {"lang": "es", "value": "Net::IMAP implementa la funcionalidad de cliente del Protocolo de Acceso a Mensajes de Internet (IMAP) en Ruby. Desde las versiones 0.4.0 hasta antes de la 0.4.24, 0.5.0 hasta antes de la 0.5.14, y 0.6.0 hasta antes de la 0.6.4, al autenticar una conexi\u00f3n con SCRAM-SHA1 o SCRAM-SHA256, un servidor hostil puede realizar un ataque de denegaci\u00f3n de servicio computacional en el proceso del cliente al enviar un valor de recuento de iteraciones grande. Este problema ha sido parcheado en las versiones 0.4.24, 0.5.14 y 0.6.4."}], "id": "CVE-2026-42256", "lastModified": "2026-07-24T19:10:00.160", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 6.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 2.8, "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": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 6.0, "baseSeverity": "MEDIUM", "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": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "PASSIVE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:H/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": "HIGH", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "security-advisories@github.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-42256", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-05-11T17:04:26.784816Z", "version": "2.0.3"}}]}, "published": "2026-05-09T20:16:28.313", "references": [{"source": "security-advisories@github.com", "tags": ["Patch"], "url": "https://github.com/ruby/net-imap/commit/158d0b505074397cdb5ceb58935e42dd2bcfa612"}, {"source": "security-advisories@github.com", "tags": ["Patch"], "url": "https://github.com/ruby/net-imap/commit/808001bc45c06f7297a7e96d341279e041a7f7f4"}, {"source": "security-advisories@github.com", "tags": ["Patch"], "url": "https://github.com/ruby/net-imap/commit/99f59eab6064955a23debd95410263ad144df758"}, {"source": "security-advisories@github.com", "tags": ["Release Notes"], "url": "https://github.com/ruby/net-imap/releases/tag/v0.4.24"}, {"source": "security-advisories@github.com", "tags": ["Release Notes"], "url": "https://github.com/ruby/net-imap/releases/tag/v0.5.14"}, {"source": "security-advisories@github.com", "tags": ["Release Notes"], "url": "https://github.com/ruby/net-imap/releases/tag/v0.6.4"}, {"source": "security-advisories@github.com", "tags": ["Mitigation", "Vendor Advisory"], "url": "https://github.com/ruby/net-imap/security/advisories/GHSA-87pf-fpwv-p7m7"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-770"}, {"lang": "en", "value": "CWE-1322"}], "source": "security-advisories@github.com", "type": "Secondary"}]}

{"bugzilla": {"description": "ruby/net-imap: ruby: Net::IMAP: Denial of Service via large iteration count in SCRAM authentication", "id": "2468500", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2468500"}, "csaw": false, "cvss3": {"cvss3_base_score": "6.5", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-606", "details": ["A flaw was found in Net::IMAP, a Ruby library for Internet Message Access Protocol (IMAP) client functionality. A hostile server can exploit this vulnerability during SCRAM-SHA1 or SCRAM-SHA256 (Salted Challenge Response Authentication Mechanism - Secure Hash Algorithm 1 or 256) authentication by sending an excessively large iteration count value. This can lead to a computational denial-of-service attack, causing the client process to become unresponsive."], "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-2026-42256", "package_state": [{"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/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-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/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:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "ruby", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "ruby4.0", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "ruby:3.3/ruby", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "ruby:3.3/ruby", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "ruby:4.0/ruby", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:hummingbird:1", "fix_state": "Fix deferred", "package_name": "ruby3.3", "product_name": "Red Hat Hardened Images"}, {"cpe": "cpe:/a:redhat:hummingbird:1", "fix_state": "Fix deferred", "package_name": "ruby3.4", "product_name": "Red Hat Hardened Images"}, {"cpe": "cpe:/a:redhat:hummingbird:1", "fix_state": "Fix deferred", "package_name": "ruby4.0", "product_name": "Red Hat Hardened Images"}], "public_date": "2026-05-09T19:38:33Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-42256\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-42256\nhttps://github.com/ruby/net-imap/commit/158d0b505074397cdb5ceb58935e42dd2bcfa612\nhttps://github.com/ruby/net-imap/commit/808001bc45c06f7297a7e96d341279e041a7f7f4\nhttps://github.com/ruby/net-imap/commit/99f59eab6064955a23debd95410263ad144df758\nhttps://github.com/ruby/net-imap/releases/tag/v0.4.24\nhttps://github.com/ruby/net-imap/releases/tag/v0.5.14\nhttps://github.com/ruby/net-imap/releases/tag/v0.6.4\nhttps://github.com/ruby/net-imap/security/advisories/GHSA-87pf-fpwv-p7m7"], "threat_severity": "Moderate"}

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