CVE-2026-58050

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A malicious SSH server can then drive the attribute-parsing loop to write past the allocation, causing a heap buffer overflow in a connecting libssh2 client."}, {"lang": "es", "value": "libssh2 hasta la versi\u00f3n 1.11.1 lee un recuento de atributos de 32 bits controlado por el atacante de una respuesta del subsistema de clave p\u00fablica y lo utiliza en la asignaci\u00f3n num_attrs * sizeof(libssh2_publickey_attribute) sin comprobaci\u00f3n de l\u00edmites, por lo que en plataformas de 32 bits la multiplicaci\u00f3n desborda a un b\u00fafer de tama\u00f1o insuficiente. Un servidor SSH malicioso puede entonces dirigir el bucle de an\u00e1lisis de atributos para escribir m\u00e1s all\u00e1 de la asignaci\u00f3n, causando un desbordamiento de b\u00fafer de pila en un cliente libssh2 que se conecta."}], "id": "CVE-2026-58050", "lastModified": "2026-10-25T17:10:00.197", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 7.0, "baseSeverity": "HIGH", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H", "version": "3.1"}, "exploitabilityScore": 2.2, "impactScore": 4.7, "source": "disclosure@vulncheck.com", "type": "Secondary"}, {"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 7.5, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "nvd@nist.gov", "type": "Primary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "HIGH", "attackRequirements": "NONE", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 8.3, "baseSeverity": "HIGH", "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:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/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": "LOW", "vulnIntegrityImpact": "LOW", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "disclosure@vulncheck.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-58050", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-06-29T12:26:56.794862Z", "version": "2.0.3"}}]}, "published": "2026-06-28T02:16:32.017", "references": [{"source": "disclosure@vulncheck.com", "tags": ["Broken Link"], "url": "https://github.com/bikini/exploitarium/tree/main/libssh2-publickey-list-calc-poc"}, {"source": "disclosure@vulncheck.com", "tags": ["Product"], "url": "https://github.com/libssh2/libssh2/blob/master/src/publickey.c"}, {"source": "disclosure@vulncheck.com", "tags": ["Third Party Advisory"], "url": "https://www.vulncheck.com/advisories/libssh2-integer-overflow-in-publickey-subsystem-attribute-allocation"}], "sourceIdentifier": "disclosure@vulncheck.com", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-190"}], "source": "disclosure@vulncheck.com", "type": "Secondary"}]}

{"bugzilla": {"description": "libssh2: libssh2: Heap buffer overflow via integer overflow in publickey attribute allocation", "id": "2493955", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2493955"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.0", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H", "status": "draft"}, "cwe": "CWE-787", "details": ["libssh2 through 1.11.1 reads an attacker-controlled 32-bit attribute count from a publickey-subsystem response and uses it in the allocation num_attrs * sizeof(libssh2_publickey_attribute) without bounds checking, so on 32-bit platforms the multiplication overflows to an undersized buffer. A malicious SSH server can then drive the attribute-parsing loop to write past the allocation, causing a heap buffer overflow in a connecting libssh2 client.", "A flaw in libssh2 allows a malicious SSH server to trigger a memory overflow by sending a manipulated attribute count. This can cause the connecting client to crash or allow unauthorized code execution."], "mitigation": {"lang": "en:us", "value": "To mitigate this issue,ensure your applications are running strictly on 64-bit architectures, which naturally prevents the integer overflow from occurring. Additionally, configure your applications to connect only to trusted, verified SSH servers."}, "name": "CVE-2026-58050", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "package_name": "libssh2", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Affected", "package_name": "libssh2", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/a:redhat:hummingbird:1", "fix_state": "Affected", "impact": "moderate", "package_name": "libssh2", "product_name": "Red Hat Hardened Images"}], "public_date": "2026-06-28T01:32:53Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-58050\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-58050\nhttps://github.com/bikini/exploitarium/tree/main/libssh2-publickey-list-calc-poc\nhttps://github.com/libssh2/libssh2/blob/master/src/publickey.c\nhttps://www.vulncheck.com/advisories/libssh2-integer-overflow-in-publickey-subsystem-attribute-allocation"], "statement": "This Moderate impact flaw in libssh2 allows a malicious SSH server to trigger a heap buffer overflow in a connecting client. By manipulating the publickey-subsystem response, an attacker could cause an integer overflow, potentially leading to denial of service or arbitrary code execution on Red Hat systems using libssh2 to establish SSH connections.\nNote: Red Hat Enterprise Linux (RHEL) 8 and newer are not affected by this flaw, as they do not ship the libssh2 package.", "threat_severity": "Moderate"}

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