IRONSMITHINTEL
HIGHCVSS8.1
|
Actively Exploited
|CISA KEV|CVE-2025-27363|Auth: none — unauthenticated|Reboot: required|Manual only

FreeType Out-of-Bounds Write Vulnerability

FreeType contains an out-of-bounds write vulnerability when attempting to parse font subglyph structures related to TrueType GX and variable font files that may allow for arbitrary code execution.

Published Mar 11, 2025 · Updated May 16, 2026
Why patchRisk explained in plain English
Worst-case scenarioIf unpatched

A remote attacker, without authentication, can achieve full data confidentiality loss, arbitrary modification of data, complete denial of service or system unavailability. Federal agencies are required to remediate by 2025-05-27 under CISA BOD 22-01.

How the attack worksNo clicks needed

This is a Out-of-bounds Write (CWE-787) vulnerability in FreeType FreeType. An out of bounds write exists in FreeType versions 2.13.0 and below (newer versions of FreeType are not vulnerable) 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. Exploitation requires remote network access, higher attack complexity, no authentication required, and no user interaction required.

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Phishing link

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Malicious file

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Server compromised

Am I affected?Quick check

Probably yes if any of these apply:

IT Security
Running freetype: v ≤ 2.13.0; debian linux: 11.0
Real-world incidentsWhat we've seen

CISA added this CVE to the Known Exploited Vulnerabilities catalog on 2025-05-06 based on evidence of active exploitation in the wild. Federal agencies required to remediate by 2025-05-27.

How to patch

Manual remediation steps

Apply the Vendor Patch

This vulnerability is in the CISA Known Exploited Vulnerabilities catalog — apply the vendor's security update as soon as possible.

CISA required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

References

    1
    NVD entry: https://nvd.nist.gov/vuln/detail/CVE-2025-27363
    1
    CISA KEV: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-27363
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