{"dataType": "CVE_RECORD", "cveMetadata": {"cveId": "CVE-2026-34085", "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca", "state": "PUBLISHED", "assignerShortName": "mitre", "dateReserved": "2026-03-25T16:54:36.761Z", "datePublished": "2026-03-25T16:54:37.187Z", "dateUpdated": "2026-03-25T16:56:57.003Z"}, "containers": {"cna": {"affected": [{"defaultStatus": "unaffected", "product": "fontconfig", "vendor": "fontconfig", "versions": [{"lessThan": "2.17.1", "status": "affected", "version": "0", "versionType": "semver"}]}], "descriptions": [{"lang": "en", "value": "fontconfig before 2.17.1 has an off-by-one error in allocation during sfnt capability handling, leading to a one-byte out-of-bounds write, and potentially a crash or code execution. This is in FcFontCapabilities in fcfreetype.c."}], "metrics": [{"cvssV3_1": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "LOW", "baseScore": 5.9, "baseSeverity": "MEDIUM", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L", "version": "3.1"}, "format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "problemTypes": [{"descriptions": [{"cweId": "CWE-193", "description": "CWE-193 Off-by-one Error", "lang": "en", "type": "CWE"}]}], "providerMetadata": {"orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca", "shortName": "mitre", "dateUpdated": "2026-03-25T16:56:57.003Z"}, "references": [{"url": "https://gitlab.freedesktop.org/fontconfig/fontconfig/-/commit/b9bec06d73340f1b5727302d13ac3df307b7febc"}, {"url": "https://gitlab.freedesktop.org/fontconfig/fontconfig/-/merge_requests/446"}, {"url": "https://gitlab.freedesktop.org/fontconfig/fontconfig/-/work_items/481"}], "x_generator": {"engine": "CVE-Request-form 0.0.1"}}}, "dataVersion": "5.2"}

{}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "fontconfig before 2.17.1 has an off-by-one error in allocation during sfnt capability handling, leading to a one-byte out-of-bounds write, and potentially a crash or code execution. This is in FcFontCapabilities in fcfreetype.c."}], "id": "CVE-2026-34085", "lastModified": "2026-03-25T17:17:09.210", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "LOW", "baseScore": 5.9, "baseSeverity": "MEDIUM", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L", "version": "3.1"}, "exploitabilityScore": 2.5, "impactScore": 3.4, "source": "cve@mitre.org", "type": "Secondary"}]}, "published": "2026-03-25T17:17:09.210", "references": [{"source": "cve@mitre.org", "url": "https://gitlab.freedesktop.org/fontconfig/fontconfig/-/commit/b9bec06d73340f1b5727302d13ac3df307b7febc"}, {"source": "cve@mitre.org", "url": "https://gitlab.freedesktop.org/fontconfig/fontconfig/-/merge_requests/446"}, {"source": "cve@mitre.org", "url": "https://gitlab.freedesktop.org/fontconfig/fontconfig/-/work_items/481"}], "sourceIdentifier": "cve@mitre.org", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-193"}], "source": "cve@mitre.org", "type": "Primary"}]}

{}

{"analysis": {"en": {"generated_at": "2026-03-25T19:09:24.796472+00:00", "value": {"mitigation_remediation": ["Upgrade fontconfig to version 2.17.1 or later to eliminate the flawed code path.", "If an immediate upgrade is not possible, restrict or validate the font files that applications load to reduce the chance of triggering the overflow.", "Stay informed by monitoring fontconfig releases and security advisories for any further guidance or patches."], "summary": {"action": "Apply Patch", "impact": "Potential Code Execution"}, "threat_synthesis": {"affected_systems": "All versions of fontconfig older than 2.17.1 are affected. Systems that link against this library\u2014Linux desktop environments, X11 servers, and any application that loads font files\u2014could be impacted. The product name is fontconfig; no specific vendor names are provided. ", "description_and_impact": "fontconfig, the default font configuration library on Linux and related systems, contains an off\u2011by\u2011one error in the sfnt capability handler. The flaw permits a one\u2011byte write past the end of a buffer, which can corrupt memory and may result in either a crash or execution of arbitrary code. The defect is classified as an off\u2011by\u2011one error (CWE\u2011193).", "risk_and_exploitability": "The CVSS score is 5.9, indicating moderate severity. No EPSS score is available, and the vulnerability is not listed in the CISA KEV catalog, so current exploitation visibility is limited. The likely attack vector is local, inferred from the fact that the flaw is triggered when fontconfig processes font files that an application or service is able to provide. If an attacker supplies a crafted font, the out\u2011of\u2011bounds write could terminate the consuming process or, in the worst case, lead to code execution with the process\u2019s privileges."}}}}, "created": "2026-03-25T21:46:45.549586+00:00", "title": "Off-by-One Vulnerability in Fontconfig May Enable Code Execution", "updated": "2026-03-25T21:46:45.549613+00:00", "vendors": []}