CVE-2026-56390

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{"affected": [{"affectedData": [{"defaultStatus": "unknown", "product": "Bison", "repo": "https://cgit.git.savannah.gnu.org/cgit/bison.git/", "vendor": "GNU", "versions": [{"status": "affected", "version": "3.8.2", "versionType": "semver"}]}], "source": "cvd@cert.pl"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:gnu:bison:3.8.2:*:*:*:*:*:*:*", "matchCriteriaId": "524B249F-965A-4AA8-9F93-54298A0F69FB", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "GNU Bison improperly handles grammar\u2011defined output paths. Grammar directives such as %output and %header allow specifying file paths, which are accepted without restriction and override caller\u2011supplied output options. \nWhen processing attacker-supplied grammar, this behavior allows directing generated files to arbitrary writable locations on the filesystem, potentially overwriting existing files accessible to the Bison process.\n\nMaintainers of this project were notified about this vulnerability, and fixed the issue in commit\u00a08d101c19d4d9aaedf83a448c925513742d4efcf0. However, they did not provide vulnerable version range. Version 3.8.2 was tested\u00a0and confirmed as vulnerable, other versions were not tested but might also be vulnerable."}, {"lang": "es", "value": "GNU Bison maneja incorrectamente las rutas de salida definidas por la gram\u00e1tica. Las directivas de gram\u00e1tica como %output y %header permiten especificar rutas de archivo, las cuales son aceptadas sin restricci\u00f3n y anulan las opciones de salida proporcionadas por el llamador.\nAl procesar gram\u00e1tica proporcionada por el atacante, este comportamiento permite dirigir los archivos generados a ubicaciones arbitrarias con permisos de escritura en el sistema de archivos, sobrescribiendo potencialmente archivos existentes accesibles para el proceso de Bison.\n\nLos mantenedores de este proyecto fueron notificados sobre esta vulnerabilidad y corrigieron el problema en el commit 8d101c19d4d9aaedf83a448c925513742d4efcf0. Sin embargo, no proporcionaron un rango de versiones vulnerables. La versi\u00f3n 3.8.2 fue probada y confirmada como vulnerable, otras versiones no fueron probadas pero tambi\u00e9n podr\u00edan ser vulnerables."}], "id": "CVE-2026-56390", "lastModified": "2026-10-23T23:10:00.157", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "NONE", "baseScore": 6.3, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "CHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:N/I:H/A:N", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 4.0, "source": "nvd@nist.gov", "type": "Primary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "LOCAL", "availabilityRequirement": "NOT_DEFINED", "baseScore": 4.6, "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": "LOW", "userInteraction": "ACTIVE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:L/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": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "LOW", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "cvd@cert.pl", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-56390", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-07-29T12:14:42.510020Z", "version": "2.0.3"}}]}, "published": "2026-07-29T11:16:49.910", "references": [{"source": "cvd@cert.pl", "tags": ["Third Party Advisory"], "url": "https://cert.pl/en/posts/2026/07/CVE-2026-56389"}, {"source": "cvd@cert.pl", "tags": ["Product"], "url": "https://cgit.git.savannah.gnu.org/cgit/bison.git/"}, {"source": "cvd@cert.pl", "tags": ["Patch"], "url": "https://cgit.git.savannah.gnu.org/cgit/bison.git/commit/?id=8d101c19d4d9aaedf83a448c925513742d4efcf0"}], "sourceIdentifier": "cvd@cert.pl", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-73"}], "source": "cvd@cert.pl", "type": "Secondary"}]}

{"bugzilla": {"description": "bison: GNU Bison: Arbitrary file overwrite via grammar-defined output paths", "id": "2508370", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2508370"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.6", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:L", "status": "draft"}, "cwe": "CWE-22", "details": ["A flaw was found in GNU Bison. When processing attacker-supplied grammar, the software improperly handles grammar-defined output paths. This allows an attacker to use directives such as %output and %header to specify arbitrary file paths. Consequently, generated files can be directed to any writable location on the filesystem, potentially overwriting existing files and leading to data integrity issues."], "name": "CVE-2026-56390", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "bison", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "package_name": "bison", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Fix deferred", "package_name": "bison", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "bison", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "bison", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Fix deferred", "package_name": "rhcos", "product_name": "Red Hat OpenShift Container Platform 4"}], "public_date": "2026-07-29T09:40:03Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-56390\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-56390\nhttps://cert.pl/en/posts/2026/07/CVE-2026-56389\nhttps://cgit.git.savannah.gnu.org/cgit/bison.git/\nhttps://cgit.git.savannah.gnu.org/cgit/bison.git/commit/?id=8d101c19d4d9aaedf83a448c925513742d4efcf0"], "threat_severity": "Moderate"}

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