ubuntu-cve-2026-18497
Vulnerability from osv_ubuntu
Published
2026-08-07 15:16
Modified
2026-08-13 17:17
Summary
Details

A heap-buffer-overflow vulnerability exists in the nothings stb TrueType library, up to version 1.26, that is used for parsing TrueType font files. The vulnerability exists in the stbtt__GetGlyphShapeTT() function within the nothings stb_truetype.h library when parsing malformed TTF (TrueType Font) files. The vulnerability resides in the glyph data parsing path. An attacker can craft a malformed TTF file with an inflated endPtsOfContours value and truncate the remaining glyph data. When an application utilizing stb_truetype.h (such as various game engines or graphics software) attempts to load, bake, or render this malformed font via stbtt_GetGlyphShape(), the parser will attempt to read past the end of the glyph data buffer, triggering the out-of-bounds read.

Severity
7.1 (High)
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libstb0",
            "binary_version": "0.0~git20190817.1.052dce1-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "libstb",
        "purl": "pkg:deb/ubuntu/libstb@0.0~git20190817.1.052dce1-1?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.0~git20190817.1.052dce1-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libstb0",
            "binary_version": "0.0~git20210910.af1a5bc+ds-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "libstb",
        "purl": "pkg:deb/ubuntu/libstb@0.0~git20210910.af1a5bc+ds-1?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.0~git20200713.b42009b+ds-1",
        "0.0~git20210910.af1a5bc+ds-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libstb0t64",
            "binary_version": "0.0~git20230129.5736b15+ds-1.2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "libstb",
        "purl": "pkg:deb/ubuntu/libstb@0.0~git20230129.5736b15+ds-1.2?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.0~git20230129.5736b15+ds-1",
        "0.0~git20230129.5736b15+ds-1.1",
        "0.0~git20230129.5736b15+ds-1.2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libstb0t64",
            "binary_version": "0.0~git20250907.fede005+ds-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "libstb",
        "purl": "pkg:deb/ubuntu/libstb@0.0~git20250907.fede005+ds-1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.0~git20241109.5c20573+ds-1",
        "0.0~git20250907.fede005+ds-1"
      ]
    }
  ],
  "aliases": [],
  "details": "A heap-buffer-overflow vulnerability exists in the nothings stb TrueType library, up to version 1.26, that is used for parsing TrueType font files. The vulnerability exists in the stbtt__GetGlyphShapeTT() function within the nothings stb_truetype.h library when parsing malformed TTF (TrueType Font) files. The vulnerability resides in the glyph data parsing path. An attacker can craft a malformed TTF file with an inflated endPtsOfContours value and truncate the remaining glyph data. When an application utilizing stb_truetype.h (such as various game engines or graphics software) attempts to load, bake, or render this malformed font via stbtt_GetGlyphShape(), the parser will attempt to read past the end of the glyph data buffer, triggering the out-of-bounds read.",
  "id": "UBUNTU-CVE-2026-18497",
  "modified": "2026-08-13T17:17:06Z",
  "published": "2026-08-07T15:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-18497"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-18497"
    },
    {
      "type": "REPORT",
      "url": "https://cwe.mitre.org/data/definitions/122.html"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/nothings/stb"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/nothings/stb/issues/1905"
    },
    {
      "type": "REPORT",
      "url": "https://kb.cert.org/vuls/id/987105"
    },
    {
      "type": "REPORT",
      "url": "https://www.kb.cert.org/vuls/id/987105"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-18497"
  ]
}



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