CVE-2026-31962

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{"affected": [{"affectedData": [{"product": "htslib", "vendor": "samtools", "versions": [{"status": "affected", "version": "< 1.21.1"}, {"status": "affected", "version": ">= 1.22, < 1.22.2"}, {"status": "affected", "version": "= 1.23"}]}], "source": "security-advisories@github.com"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:htslib:htslib:*:*:*:*:*:*:*:*", "matchCriteriaId": "A069D6B6-FFF6-4DB7-9811-A568ECC4B288", "versionEndExcluding": "1.21.1", "vulnerable": true}, {"criteria": "cpe:2.3:a:htslib:htslib:*:*:*:*:*:*:*:*", "matchCriteriaId": "D9D525C8-C8AD-4368-A396-EB4D9DA02B1C", "versionEndExcluding": "1.22.2", "versionStartIncluding": "1.22", "vulnerable": true}, {"criteria": "cpe:2.3:a:htslib:htslib:1.23:*:*:*:*:*:*:*", "matchCriteriaId": "AAA6BBB2-76F3-4372-9BAE-FDE157401EFD", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "HTSlib is a library for reading and writing bioinformatics file formats. CRAM is a compressed format which stores DNA sequence alignment data. While most alignment records store DNA sequence and quality values, the format also allows them to omit this data in certain cases to save space. Due to some quirks of the CRAM format, it is necessary to handle these records carefully as they will actually store data that needs to be consumed and then discarded. Unfortunately the `cram_decode_seq()` did not handle this correctly in some cases. Where this happened it could result in reading a single byte from beyond the end of a heap allocation, followed by writing a single attacker-controlled byte to the same location. Exploiting this bug causes a heap buffer overflow. If a user opens a file crafted to exploit this issue, it could lead to the program crashing, or overwriting of data and heap structures in ways not expected by the program. It may be possible to use this to obtain arbitrary code execution. Versions 1.23.1, 1.22.2 and 1.21.1 include fixes for this issue. There is no workaround for this issue."}, {"lang": "es", "value": "HTSlib es una biblioteca para leer y escribir formatos de archivo bioinform\u00e1ticos. CRAM es un formato comprimido que almacena datos de alineaci\u00f3n de secuencias de ADN. Si bien la mayor\u00eda de los registros de alineaci\u00f3n almacenan valores de secuencia de ADN y de calidad, el formato tambi\u00e9n permite omitir estos datos en ciertos casos para ahorrar espacio. Debido a algunas peculiaridades del formato CRAM, es necesario manejar estos registros con cuidado, ya que en realidad almacenar\u00e1n datos que deben ser consumidos y luego descartados. Desafortunadamente, `cram_decode_seq()` no manej\u00f3 esto correctamente en algunos casos. Donde esto ocurri\u00f3, podr\u00eda resultar en la lectura de un solo byte m\u00e1s all\u00e1 del final de una asignaci\u00f3n de mont\u00f3n, seguido de la escritura de un solo byte controlado por el atacante en la misma ubicaci\u00f3n. Explotar este error causa un desbordamiento de b\u00fafer de mont\u00f3n. Si un usuario abre un archivo dise\u00f1ado para explotar este problema, podr\u00eda provocar el bloqueo del programa o la sobrescritura de datos y estructuras de mont\u00f3n de formas no esperadas por el programa. Podr\u00eda ser posible usar esto para obtener ejecuci\u00f3n de c\u00f3digo arbitrario. Las versiones 1.23.1, 1.22.2 y 1.21.1 incluyen correcciones para este problema. No hay una soluci\u00f3n alternativa para este problema."}], "id": "CVE-2026-31962", "lastModified": "2026-06-17T10:34:50.920", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 8.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 5.9, "source": "nvd@nist.gov", "type": "Primary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 8.8, "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:L/AT:N/PR:N/UI:N/VC:L/VI:H/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": "HIGH", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "security-advisories@github.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-31962", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-03-18T18:37:15.989459Z", "version": "2.0.3"}}]}, "published": "2026-03-18T18:16:28.190", "references": [{"source": "security-advisories@github.com", "tags": ["Patch"], "url": "https://github.com/samtools/htslib/commit/d799b54c6401879187bba4741be83ff590ac73e3"}, {"source": "security-advisories@github.com", "tags": ["Patch", "Vendor Advisory"], "url": "https://github.com/samtools/htslib/security/advisories/GHSA-xxmp-v7h3-gpwp"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-122"}, {"lang": "en", "value": "CWE-125"}, {"lang": "en", "value": "CWE-129"}, {"lang": "en", "value": "CWE-787"}], "source": "security-advisories@github.com", "type": "Secondary"}]}

{"bugzilla": {"description": "htslib: htslib: Heap buffer overflow leading to arbitrary code execution via crafted CRAM file", "id": "2448750", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2448750"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.3", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H", "status": "draft"}, "cwe": "CWE-1284", "details": ["A flaw was found in htslib, a library for reading and writing bioinformatics file formats. A local user could exploit a heap buffer overflow vulnerability by opening a specially crafted CRAM file. This flaw occurs due to incorrect handling of certain CRAM format records, leading to reading and writing a single byte beyond a heap allocation. Successful exploitation could result in a program crash, data corruption, or potentially arbitrary code execution."], "name": "CVE-2026-31962", "public_date": "2026-03-18T18:08:26Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-31962\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-31962\nhttps://github.com/samtools/htslib/commit/d799b54c6401879187bba4741be83ff590ac73e3\nhttps://github.com/samtools/htslib/security/advisories/GHSA-xxmp-v7h3-gpwp"], "statement": "This is an IMPORTANT heap buffer overflow flaw in the HTSlib CRAM reader. The vulnerability can be triggered when processing a specially crafted CRAM file, potentially leading to application crashes, data corruption, or arbitrary code execution. This issue affects Red Hat Community Projects, including EPEL and Fedora.", "threat_severity": "Important"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,1.21.1)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[1.22,1.22.2)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "1.23"}}], "enrichment": {"confidence": 100.0, "confidence_source": "cna", "scores": [{"score": 100.0, "source": "cna"}]}, "product": "htslib", "vendor": "samtools"}], "analysis": {"en": {"generated_at": "2026-03-19T18:26:10.987477+00:00", "value": {"mitigation_remediation": ["Upgrade htslib to version 1.23.1 or later, or to 1.22.2/1.21.1 where applicable.", "Rebuild dependent tools such as samtools against the patched library.", "Avoid opening untrusted CRAM files until the library is updated.", "Monitor vendor advisories for additional patches or mitigations."], "summary": {"action": "Apply Patch", "impact": "Remote Code Execution"}, "threat_synthesis": {"affected_systems": "Affected systems are the HTSlib library used by samtools. Vulnerable releases include all versions of htslib older than the patch commits, specifically those preceding version 1.23.1, except for releases that were subsequently fixed such as 1.22.2 and 1.21.1. Administrators should verify the installed htslib version against the advisory to determine whether a patch is required.", "description_and_impact": "The vulnerability is a heap buffer overflow in the cram_decode_seq function of HTSlib, triggered when improperly handling CRAM records that omit sequence data. The overflow allows an attacker\u2011controlled byte to be written beyond the bounds of a heap allocation, potentially corrupting memory and enabling arbitrary code execution. The weakness corresponds to several CWE identifiers, including CWE\u2011122, CWE\u2011125, CWE\u20111284, CWE\u2011129, and CWE\u2011787.", "risk_and_exploitability": "The severity of the flaw is high with a CVSS score of 8.8, but its EPSS score is less than 1% and it is not listed in the CISA KEV catalog, indicating a lower likelihood of exploitation in the wild. Exploitation requires an attacker to supply a malicious CRAM file that the application processes, meaning the attack vector is local or remote file ingestion. If successful, the defect can lead to program termination or memory corruption that could be leveraged for arbitrary code execution, thus representing a significant security risk when untrusted data is processed."}}}}, "created": "2026-03-19T08:55:46.249755+00:00", "updated": "2026-03-25T11:52:29.276532+00:00", "vendors": ["samtools", "samtools$PRODUCT$htslib"]}