CVE-2025-27363 — freetype
HIGHCVE-2025-27363 is a high-severity (CVSS 8.1) Out-of-bounds Write vulnerability. It is in CISA's Known Exploited Vulnerabilities catalog (added 2025-05-06) — treat it as actively exploited and patch now. No vendor fix is recorded yet; mitigation options are listed below.
Exploitation Status
Actively exploited in the wild
- Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2025-05-06. Federal agencies were required to remediate by 2025-05-27.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2025-27363.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2025-27363 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 394,803 CVEs with a current EPSS score, this one falls in the 10–50% band (highlighted). Counts from FIRST.org, log-scaled.
Description
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.
Affected Products
debian linuxdebianfreetypefreetypeResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
VulnerabilityDetect
Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).
Remediation status
No fixed release is recorded for CVE-2025-27363 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.
Mitigate without a patch
Stop feeding it untrusted input: reject or quarantine files and payloads from unverified sources until you can upgrade, restrict accepted formats to the ones you actually need, and run the parsing or decoding step in a least-privileged sandbox or short-lived worker so a crash or corrupted read cannot reach the rest of the process.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
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…
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.Source: Red Hat security advisory for CVE-2025-27363 (CC BY 4.0)
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Enterprise Linux 7 Extended Lifecycle Support | freetype-0:2.8-15.el7_9.1 | RHSA-2025:3395 |
| Red Hat Enterprise Linux 8 | mingw-freetype-0:2.8-3.el8_10.1 | RHSA-2025:8292 |
| Red Hat Enterprise Linux 8 | freetype-0:2.9.1-10.el8_10 | RHSA-2025:3421 |
| Red Hat Enterprise Linux 8.2 Advanced Update Support | spice-client-win-0:8.2-1 | RHSA-2025:9380 |
| Red Hat Enterprise Linux 8.2 Advanced Update Support | freetype-0:2.9.1-5.el8_2.1 | RHSA-2025:3393 |
| Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | spice-client-win-0:8.4-2 | RHSA-2025:8253 |
| Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | freetype-0:2.9.1-7.el8_4 | RHSA-2025:3382 |
| Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support | spice-client-win-0:8.6-1 | RHSA-2025:8219 |
Frequently Asked Questions
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