CVE-2026-34085

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.

Database specific

{
    "cwe_ids": [
        "CWE-193"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34085.json",
    "cna_assigner": "mitre"
}

References

Affected packages

Git / gitlab.freedesktop.org/fontconfig/fontconfig

Affected ranges

Type

GIT

Repo

https://gitlab.freedesktop.org/fontconfig/fontconfig

Events

Introduced

a7a03d6ce093042d1ad4c5cf68746f44b03d8bda

Fixed

b9bec06d73340f1b5727302d13ac3df307b7febc

Database specific

{
    "cpe": "cpe:2.3:a:fontconfig_project:fontconfig:2.17.0:*:*:*:*:*:*:*",
    "source": [
        "CPE_STRING",
        "REFERENCES"
    ],
    "extracted_events": [
        {
            "introduced": "2.17.0"
        },
        {
            "last_affected": "2.17.0"
        }
    ]
}

Affected versions

2.*

2.17.0

Database specific

vanir_signatures_modified

"2026-07-15T19:48:10Z"

vanir_signatures

[
    {
        "signature_type": "Line",
        "target": {
            "file": "src/fcfreetype.c"
        },
        "deprecated": false,
        "source": "https://gitlab.freedesktop.org/fontconfig/fontconfig@b9bec06d73340f1b5727302d13ac3df307b7febc",
        "id": "CVE-2026-34085-45ef1721",
        "signature_version": "v1",
        "digest": {
            "line_hashes": [
                "338340049756908944638127367645014270671",
                "268265478117448297596468193855047314435",
                "225805937722339647865978530876903344264",
                "214071455402570792325521226127506101614"
            ],
            "threshold": 0.9
        }
    },
    {
        "signature_type": "Function",
        "target": {
            "file": "src/fcfreetype.c",
            "function": "FcFontCapabilities"
        },
        "deprecated": false,
        "source": "https://gitlab.freedesktop.org/fontconfig/fontconfig@b9bec06d73340f1b5727302d13ac3df307b7febc",
        "id": "CVE-2026-34085-91fe36e2",
        "signature_version": "v1",
        "digest": {
            "function_hash": "167811288294678018177566407554085947143",
            "length": 1198.0
        }
    }
]

source

"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-34085.json"