An out of bounds write exists in FreeType versions 2.13.0 and below when attempting to parse font subglyph structures related to TrueType GX and variable font files. The vulnerable code assigns a signed short value to an unsigned long and then adds a static value causing it to wrap around and allocate too small of a heap buffer. The code then writes up to 6 signed long integers out of bounds relative to this buffer. This may result in arbitrary code execution. This vulnerability may have been exploited in the wild.

References

• https://nvd.nist.gov/vuln/detail/CVE-2025-27363
• https://www.facebook.com/security/advisories/cve-2025-27363
• http://www.openwall.com/lists/oss-security/2025/03/13/1
• http://www.openwall.com/lists/oss-security/2025/03/13/2
• http://www.openwall.com/lists/oss-security/2025/03/13/3
• http://www.openwall.com/lists/oss-security/2025/03/13/8
• http://www.openwall.com/lists/oss-security/2025/03/13/11
• http://www.openwall.com/lists/oss-security/2025/03/13/12
• http://www.openwall.com/lists/oss-security/2025/03/14/1
• http://www.openwall.com/lists/oss-security/2025/03/14/2
• http://www.openwall.com/lists/oss-security/2025/03/14/3
• http://www.openwall.com/lists/oss-security/2025/03/14/4
• https://lists.debian.org/debian-lts-announce/2025/03/msg00030.html
• https://source.android.com/docs/security/bulletin/2025-05-01
• http://www.openwall.com/lists/oss-security/2025/05/06/3