CVE-2026-39855

{"id": "CVE-2026-39855", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-39855", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-04-09T19:12:57.585841Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 5.5, "attackVector": "LOCAL", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "REQUIRED", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 1.8}]}, "affected": [{"source": "security-advisories@github.com", "affectedData": [{"vendor": "mtrojnar", "product": "osslsigncode", "versions": [{"status": "affected", "version": "< 2.13"}]}]}], "published": "2026-04-09T17:16:29.140", "references": [{"url": "https://github.com/mtrojnar/osslsigncode/commit/2a5409b7c4b6c6fad2b093531e8fea6cf08e1568", "tags": ["Patch"], "source": "security-advisories@github.com"}, {"url": "https://github.com/mtrojnar/osslsigncode/releases/tag/2.13", "tags": ["Product", "Release Notes"], "source": "security-advisories@github.com"}, {"url": "https://github.com/mtrojnar/osslsigncode/security/advisories/GHSA-76vv-x5rr-q3mr", "tags": ["Patch", "Vendor Advisory"], "source": "security-advisories@github.com"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-125"}, {"lang": "en", "value": "CWE-190"}, {"lang": "en", "value": "CWE-191"}]}], "descriptions": [{"lang": "en", "value": "osslsigncode is a tool that implements Authenticode signing and timestamping. Prior to 2.13, an integer underflow vulnerability exists in osslsigncode version 2.12 and earlier in the PE page-hash computation code (pe_page_hash_calc()). When page hash processing is performed on a PE file, the function subtracts hdrsize from pagesize without first validating that pagesize >= hdrsize. If a malicious PE file sets SizeOfHeaders (hdrsize) larger than SectionAlignment (pagesize), the subtraction underflows and produces a very large unsigned length. The code allocates a zero-filled buffer of pagesize bytes and then attempts to hash pagesize - hdrsize bytes from that buffer. After the underflow, this results in an out-of-bounds read from the heap and can crash the process. The vulnerability can be triggered while signing a malicious PE file with page hashing enabled (-ph), or while verifying a malicious signed PE file that already contains page hashes. Verification of an already signed file does not require the verifier to pass -ph. This vulnerability is fixed in 2.13."}, {"lang": "es", "value": "osslsigncode es una herramienta que implementa la firma Authenticode y el sellado de tiempo. Antes de la versi\u00f3n 2.13, existe una vulnerabilidad de desbordamiento negativo de enteros en osslsigncode versi\u00f3n 2.12 y anteriores en el c\u00f3digo de c\u00e1lculo de hash de p\u00e1gina PE (pe_page_hash_calc()). Cuando se realiza el procesamiento de hash de p\u00e1gina en un archivo PE, la funci\u00f3n resta hdrsize de pagesize sin validar primero que pagesize >= hdrsize. Si un archivo PE malicioso establece SizeOfHeaders (hdrsize) mayor que SectionAlignment (pagesize), la resta sufre un desbordamiento negativo y produce una longitud sin signo muy grande. El c\u00f3digo asigna un b\u00fafer rellenado con ceros de pagesize bytes y luego intenta aplicar hash a pagesize - hdrsize bytes de ese b\u00fafer. Despu\u00e9s del desbordamiento negativo, esto resulta en una lectura fuera de l\u00edmites de la pila y puede bloquear el proceso. La vulnerabilidad puede ser activada mientras se firma un archivo PE malicioso con el hash de p\u00e1gina habilitado (-ph), o mientras se verifica un archivo PE firmado malicioso que ya contiene hashes de p\u00e1gina. La verificaci\u00f3n de un archivo ya firmado no requiere que el verificador pase -ph. Esta vulnerabilidad est\u00e1 corregida en la versi\u00f3n 2.13."}], "lastModified": "2026-10-26T22:10:00.163", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:osslsigncode_project:osslsigncode:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "3F16716F-B2C3-41F9-B32B-CFD011129F12", "versionEndExcluding": "2.13"}], "operator": "OR"}]}], "sourceIdentifier": "security-advisories@github.com"}