yangjincheng1998 () gmail com writes: Hello oss-security,

[...]

== Upstream maintainer response == We reported this downstream impact to FontForge upstream as https://github.com/fontforge/fontforge/issues/5799 (2026-04-15). The issue was closed within hours under "Community-guidelines #D1", which states that the project does not accept security reports without an accompanying fix PR. I'll note that the linked #D1 guidelines [0] say: FontForge SHOULD NOT, EVER receive untrusted input. Most users only use it to edit their own fonts and sometimes popular open-source fonts. Even if we fix all the issues findable with automated tools, there are many, many memory bugs in FontForge. Of course, there's the usual question of whether all users and possibly scripts invoking FontForge are aware of this, but I don't think this is an unreasonable position for a project to have by itself.

[0] https://github.com/fontforge/fontforge/wiki/Community-guidelines#D1 Context: ZDI submitted 12 unrelated FontForge CVEs in 2025-12 and received the same response (https://github.com/fontforge/fontforge/issues/5706).

We post here so distributors and downstream packagers have a public, independent record of the FontForge -> FreeType linkage status, and can verify their own builds.

[...] sam

Hello oss-security,

This is an information-only post documenting a downstream impact and maintainer response for an existing, already-public CVE.

== CVE == CVE-2025-27363 -- FreeType <= 2.13.2 heap-buffer-overflow in loadtruetypeglyph(), src/truetype/ttgload.c (~line 1929). NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-27363 Fix: FreeType 2.13.3, upstream commit a1e5a9df.

== Downstream impact: FontForge == FontForge (https://github.com/fontforge/fontforge) links FreeType to parse and process font files. When built or run against FreeType <= 2.13.2, FontForge inherits the heap-buffer-overflow when opening a maliciously crafted TrueType font.

We confirmed the issue with AddressSanitizer against FreeType 2.13.0 (common in distributions that have not backported the fix):

==ERROR: AddressSanitizer: heap-buffer-overflow WRITE of size 16 at ttgload.c:1929 in loadtruetypeglyph 0 bytes to the right of 16-byte region allocated at ttgload.c:1909

Recommended action for distributors and packagers: ensure FontForge is built/linked against FreeType >= 2.13.3, or apply the upstream fix (commit a1e5a9df).

== Upstream maintainer response == We reported this downstream impact to FontForge upstream as https://github.com/fontforge/fontforge/issues/5799 (2026-04-15). The issue was closed within hours under "Community-guidelines #D1", which states that the project does not accept security reports without an accompanying fix PR.

Context: ZDI submitted 12 unrelated FontForge CVEs in 2025-12 and received the same response (https://github.com/fontforge/fontforge/issues/5706).

We post here so distributors and downstream packagers have a public, independent record of the FontForge -> FreeType linkage status, and can verify their own builds.

== Reproducer == Public PoC: https://github.com/francozappa/poc-CVE-2025-27363 Build/run FontForge against FreeType 2.13.0 or 2.13.2 with the PoC TTF to reproduce.

Regards, vulgraph (Academic security research; PhD work on 1-day vulnerability propagation across forks and downstream consumers.)

FontForge SFD File Parsing Improper Validation of Array Index Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of FontForge. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.

The specific flaw exists within the parsing of SFD files. The issue results from the lack of proper validation of user-supplied data, which can result in a write past the end of an allocated array. An attacker can leverage this vulnerability to execute code in the context of the current user. Was ZDI-CAN-28563.

FontForge GUtils BMP File Parsing Heap-based Buffer Overflow Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of FontForge. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.

The specific flaw exists within the parsing of pixels within BMP files. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a heap-based buffer. An attacker can leverage this vulnerability to execute code in the context of the current user. Was ZDI-CAN-27517.

FontForge SFD File Parsing Use-After-Free Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of FontForge. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.

The specific flaw exists within the parsing of SFD files. The issue results from the lack of validating the existence of an object prior to performing operations on the object. An attacker can leverage this vulnerability to execute code in the context of the current user. Was ZDI-CAN-28564.

FontForge SFD File Parsing Heap-based Buffer Overflow Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of FontForge. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.

The specific flaw exists within the parsing of SFD files. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a heap-based buffer. An attacker can leverage this vulnerability to execute code in the context of the current user. Was ZDI-CAN-28543.

FontForge GUtils BMP File Parsing Heap-based Buffer Overflow Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of FontForge. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.

The specific flaw exists within the parsing of pixels within BMP files. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a heap-based buffer. An attacker can leverage this vulnerability to execute code in the context of the current user. Was ZDI-CAN-27517.

FontForge GUtils XBM File Parsing Integer Overflow Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of FontForge. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.

The specific flaw exists within the parsing of pixels within XBM files. The issue results from the lack of proper validation of user-supplied data, which can result in an integer overflow before allocating a buffer. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-27865.

FontForge GUtils SGI File Parsing Heap-based Buffer Overflow Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of FontForge. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.

The specific flaw exists within the parsing of scanlines within SGI files. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a heap-based buffer. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-27920.

FontForge SFD File Parsing Deserialization of Untrusted Data Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of FontForge. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.

The specific flaw exists within the parsing of SFD files. The issue results from the lack of proper validation of user-supplied data, which can result in deserialization of untrusted data. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-28198.

FontForge SFD File Parsing Use-After-Free Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of FontForge. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.

The specific flaw exists within the parsing of SFD files. The issue results from the lack of validating the existence of an object prior to performing operations on the object. An attacker can leverage this vulnerability to execute code in the context of the current user. Was ZDI-CAN-28525.

FontForge SFD File Parsing Heap-based Buffer Overflow Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of FontForge. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.

The specific flaw exists within the parsing of SFD files. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a heap-based buffer. An attacker can leverage this vulnerability to execute code in the context of the current user. Was ZDI-CAN-28543.

FontForge SFD File Parsing Heap-based Buffer Overflow Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of FontForge. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.

The specific flaw exists within the parsing of SFD files. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a heap-based buffer. An attacker can leverage this vulnerability to execute code in the context of the current user. Was ZDI-CAN-28544.

FontForge PFB File Parsing Stack-based Buffer Overflow Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of FontForge. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.

The specific flaw exists within the parsing of PFB files. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of the current user. Was ZDI-CAN-28546.

FontForge SFD File Parsing Heap-based Buffer Overflow Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of FontForge. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.

The specific flaw exists within the parsing of SFD files. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a heap-based buffer. An attacker can leverage this vulnerability to execute code in the context of the current user. Was ZDI-CAN-28547.

FontForge SFD File Parsing Improper Validation of Array Index Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of FontForge. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.

The specific flaw exists within the parsing of SFD files. The issue results from the lack of proper validation of user-supplied data, which can result in a write past the end of an allocated array. An attacker can leverage this vulnerability to execute code in the context of the current user. Was ZDI-CAN-28562.

FontForge SFD File Parsing Improper Validation of Array Index Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of FontForge. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.

The specific flaw exists within the parsing of SFD files. The issue results from the lack of proper validation of user-supplied data, which can result in a write past the end of an allocated array. An attacker can leverage this vulnerability to execute code in the context of the current user. Was ZDI-CAN-28563.

FontForge SFD File Parsing Use-After-Free Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of FontForge. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.

The specific flaw exists within the parsing of SFD files. The issue results from the lack of validating the existence of an object prior to performing operations on the object. An attacker can leverage this vulnerability to execute code in the context of the current user. Was ZDI-CAN-28564.

This vulnerability allows remote attackers to execute arbitrary code on affected installations of FontForge. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the parsing of SFD files. The issue results from the lack of validating the existence of an object prior to performing operations on the object. An attacker can leverage this vulnerability to execute code in the context of the current user.

This vulnerability allows remote attackers to execute arbitrary code on affected installations of FontForge. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the parsing of SFD files. The issue results from the lack of proper validation of user-supplied data, which can result in a write past the end of an allocated array. An attacker can leverage this vulnerability to execute code in the context of the current user.

This vulnerability allows remote attackers to execute arbitrary code on affected installations of FontForge. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the parsing of SFD files. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a heap-based buffer. An attacker can leverage this vulnerability to execute code in the context of the current user.

This vulnerability allows remote attackers to execute arbitrary code on affected installations of FontForge. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the parsing of PFB files. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of the current user.

This vulnerability allows remote attackers to execute arbitrary code on affected installations of FontForge. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the parsing of scanlines within SGI files. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a heap-based buffer. An attacker can leverage this vulnerability to execute code in the context of the current process.

This vulnerability allows remote attackers to execute arbitrary code on affected installations of FontForge. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the parsing of SFD files. The issue results from the lack of validating the existence of an object prior to performing operations on the object. An attacker can leverage this vulnerability to execute code in the context of the current user.

This vulnerability allows remote attackers to execute arbitrary code on affected installations of FontForge. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the parsing of SFD files. The issue results from the lack of proper validation of user-supplied data, which can result in a write past the end of an allocated array. An attacker can leverage this vulnerability to execute code in the context of the current user.

This vulnerability allows remote attackers to execute arbitrary code on affected installations of FontForge. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the parsing of SFD files. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a heap-based buffer. An attacker can leverage this vulnerability to execute code in the context of the current user.

This vulnerability allows remote attackers to execute arbitrary code on affected installations of FontForge. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the parsing of PFB files. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of the current user.

This vulnerability allows remote attackers to execute arbitrary code on affected installations of FontForge. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the parsing of scanlines within SGI files. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a heap-based buffer. An attacker can leverage this vulnerability to execute code in the context of the current process.

This vulnerability allows remote attackers to execute arbitrary code on affected installations of FontForge. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the parsing of SFD files. The issue results from the lack of proper validation of user-supplied data, which can result in deserialization of untrusted data. An attacker can leverage this vulnerability to execute code in the context of the current process.

This vulnerability allows remote attackers to execute arbitrary code on affected installations of FontForge. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the parsing of SFD files. The issue results from the lack of proper validation of user-supplied data, which can result in deserialization of untrusted data. An attacker can leverage this vulnerability to execute code in the context of the current process.