CVE-2025-27363
Description
A flaw was found in FreeType. In affected versions, an out-of-bounds write condition may be triggered 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 a heap buffer that is too small. The code then writes up to 6 signed long integers out of bounds relative to this buffer. This issue could result in arbitrary code execution or other undefined behavior.
Statement
This vulnerability stems from improper handling of data types within the FreeType library during the parsing of font subglyph structures. This could causes incorrect calculations that result in heap buffer allocation being too small. This could allow the library write data beyond the allocated buffer, affecting adjacent memory areas, leading into arbitrary code executions compromising the entire system and system stability such as misleading behaviors in applications which relies on FreeType, or causing possible crashes impacting the entire system.
Mitigation
By restricting the sources from which font files can be loaded allowing only fonts from trusted sources, as well as validating the input for font files to avoid malformed font structures or any data which could trigger the vulnerability would reduce the risk and mitigate this vulnerability until the fix is provided.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 8.1 | 8.1 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | High | High | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | High | High | N/A |
| Integrity Impact | High | High | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Integrity
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands
Write operations could cause memory corruption. In some cases, an adversary can modify control data such as return addresses in order to execute unexpected code.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
Attempting to access out-of-range, invalid, or unauthorized memory could cause the product to crash.
Other
Technical Impact: Unexpected State
Subsequent write operations can produce undefined or unexpected results.
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