CVE-2025-27363FreeType Out-of-Bounds Write Vulnerability
CVE-2025-27363 is a out-of-bounds write in FreeType, rated high (8.1 on CVSS 3.1).
Why this priority: Exploited in the wild: listed in CISA's KEV catalog.
Published · Updated · NVD status: Analyzed
What it is
Code writes past the end of a buffer, corrupting memory in ways an attacker can often turn into code execution.
How it is reached
An attacker can exploit it over the network, without an account, and nobody has to click anything. Success also depends on conditions the attacker does not fully control.
What an attacker gains
A successful attack can read the data it protects, change data or behaviour and take it offline. In practice, this kind of flaw lets an attacker crash the process, read memory, or in the worst case run code.
Is it being exploited?
CISA added it to the Known Exploited Vulnerabilities catalog on 2025-05-06: it is being exploited in the wild. EPSS estimates a 28% chance of exploitation activity in the next 30 days, higher than 98% of scored CVEs.
What to do
- Treat it as urgent: it is on CISA's KEV list. CISA's deadline for US federal agencies: 2025-05-27.
- No fixed version is listed yet. Find every place FreeType runs, watch the references for a fix, and plan a replacement if it is no longer supported.
- While there is no fix, keep it off the internet or behind a VPN, allowlist or authenticating proxy.
- Check exposed instances for signs of compromise, not only for the version.
Description from NVD
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.
What this means for your architecture.
A CVE names a product. Whether it matters depends on where that product sits in your systems: what reaches it, which trust boundary it guards and what it can reach once compromised. Veriom maps your components, their relationships and your trust boundaries from your code, cloud and delivery evidence, so you can see where a component like this sits. The radar itself does not look at your systems.
Components it touches
- Operating systems on servers, workstations or devices. Everything on the host inherits the flaw.
- Native code: operating systems, browsers and firmware. The flaw sits wherever native code reads untrusted data.
- Network appliances and media or file parsers. The flaw sits wherever native code reads untrusted data.
Trust boundaries in play
- Internet-facing entry points. No account is needed. Any instance reachable from outside your perimeter, through a load balancer, gateway, VPN or exposed admin port, is in scope.
- Wherever native code reads untrusted data. An attacker who crosses it can crash the process, read memory, or in the worst case run code.
Questions to answer about your own systems
- Where does FreeType run in your systems, and at which version?
- Which of those instances can be reached from the internet or partner networks?
- What can it reach once compromised: which data stores, secrets and services?
Read more
Advisories
More reading
- www.openwall.com/lists/oss-security/2025/03/13/1
- www.openwall.com/lists/oss-security/2025/03/13/11
- www.openwall.com/lists/oss-security/2025/03/13/12
- www.openwall.com/lists/oss-security/2025/03/13/2
- www.openwall.com/lists/oss-security/2025/03/13/3
- www.openwall.com/lists/oss-security/2025/03/13/8
- www.openwall.com/lists/oss-security/2025/03/14/1
- www.openwall.com/lists/oss-security/2025/03/14/2
- www.openwall.com/lists/oss-security/2025/03/14/3
- www.openwall.com/lists/oss-security/2025/03/14/4
- www.openwall.com/lists/oss-security/2025/05/06/3
- www.openwall.com/lists/oss-security/2026/04/16/5
Sources
- CVE records and CVSS scores from the NVD CVE API. This product uses the NVD API but is not endorsed or certified by the NVD.
- Exploitation status from CISA’s Known Exploited Vulnerabilities catalog.
- Exploit likelihood from FIRST’s Exploit Prediction Scoring System (EPSS), refreshed daily.
- Explanations are written by Veriom from fixed templates over each record’s data, not by a person reviewing each CVE. Descriptions are quoted from the records as published.