CVE-2026-56114

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Attackers can send a crafted DHCPv6 ADVERTISE message containing an IA_PD IAPREFIX /0 with a valid OPTION_PD_EXCLUDE using an exclude prefix length of /121 through /128 to trigger the out-of-bounds write and potentially corrupt adjacent stack memory."}, {"lang": "es", "value": "dhcpcd hasta 10.3.2, corregido en el commit 2f00c7b, contiene una vulnerabilidad de escritura fuera de l\u00edmites de pila de un byte en dhcp6_makemessage() en src/dhcp6.c que permite a atacantes no autenticados en el mismo enlace escribir m\u00e1s all\u00e1 de un b\u00fafer local fijo serializando un cuerpo de opci\u00f3n RFC6603 OPTION_PD_EXCLUDE sobredimensionado. Los atacantes pueden enviar un mensaje DHCPv6 ADVERTISE manipulado que contiene un IA_PD IAPREFIX /0 con un OPTION_PD_EXCLUDE v\u00e1lido utilizando una longitud de prefijo de exclusi\u00f3n de /121 a /128 para activar la escritura fuera de l\u00edmites y potencialmente corromper la memoria de pila adyacente."}], "id": "CVE-2026-56114", "lastModified": "2026-10-25T23:10:00.167", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "HIGH", "attackVector": "ADJACENT_NETWORK", "availabilityImpact": "HIGH", "baseScore": 5.3, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 1.6, "impactScore": 3.6, "source": "disclosure@vulncheck.com", "type": "Secondary"}, {"cvssData": {"attackComplexity": "LOW", "attackVector": "ADJACENT_NETWORK", "availabilityImpact": "HIGH", "baseScore": 6.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/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": "ADJACENT", "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": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/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": "disclosure@vulncheck.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-56114", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-06-24T14:02:46.769704Z", "version": "2.0.3"}}]}, "published": "2026-06-23T17:17:09.163", "references": [{"source": "disclosure@vulncheck.com", "tags": ["Patch"], "url": "https://github.com/NetworkConfiguration/dhcpcd/commit/2f00c7bfc408b6582d331932dfa47829c4819029"}, {"source": "disclosure@vulncheck.com", "tags": ["Third Party Advisory"], "url": "https://www.vulncheck.com/advisories/dhcpcd-stack-out-of-bounds-write-in-dhcp6-makemessage"}], "sourceIdentifier": "disclosure@vulncheck.com", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-787"}], "source": "disclosure@vulncheck.com", "type": "Secondary"}]}

{"bugzilla": {"description": "dhcpcd: dhcpcd: Denial of Service due to stack out-of-bounds write via crafted DHCPv6 message", "id": "2491842", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2491842"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.3", "cvss3_scoring_vector": "CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-787", "details": ["A flaw was found in dhcpcd. An unauthenticated attacker on the same network link could exploit a one-byte stack out-of-bounds write vulnerability in the `dhcp6_makemessage()` function. By sending a specially crafted DHCPv6 ADVERTISE message with an oversized option, the attacker can write beyond a buffer, potentially corrupting adjacent memory. This could lead to a denial of service."], "name": "CVE-2026-56114", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "dhcpcd", "product_name": "Red Hat Enterprise Linux 10"}], "public_date": "2026-06-23T16:08:10Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-56114\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-56114\nhttps://github.com/NetworkConfiguration/dhcpcd/commit/2f00c7bfc408b6582d331932dfa47829c4819029\nhttps://www.vulncheck.com/advisories/dhcpcd-stack-out-of-bounds-write-in-dhcp6-makemessage"], "threat_severity": "Moderate"}

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