Sean Barrett nothings stb up to 1.26 TrueType font file Parser stb_truetype.h stbtt__GetGlyphShapeTT heap-based overflow

Summaryinfo

A vulnerability, which was classified as critical, has been found in Sean Barrett nothings stb up to 1.26. This issue affects the function stbtt__GetGlyphShapeTT of the file stb_truetype.h of the component TrueType font file Parser. The manipulation leads to heap-based overflow. This vulnerability is uniquely identified as CVE-2026-18497. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability was found in Sean Barrett nothings stb up to 1.26. It has been rated as critical. This issue affects the function stbtt__GetGlyphShapeTT of the file stb_truetype.h of the component TrueType font file Parser. The manipulation with an unknown input leads to a heap-based overflow vulnerability. Using CWE to declare the problem leads to CWE-122. A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc(). Impacted is confidentiality, integrity, and availability. The summary by CVE is:

A heap-buffer-overflow vulnerability exists in the nothings stb TrueType library, up to version 1.26, that is used for parsing TrueType font files. The vulnerability exists in the stbtt__GetGlyphShapeTT() function within the nothings stb_truetype.h library when parsing malformed TTF (TrueType Font) files. The vulnerability resides in the glyph data parsing path. An attacker can craft a malformed TTF file with an inflated endPtsOfContours value and truncate the remaining glyph data. When an application utilizing stb_truetype.h (such as various game engines or graphics software) attempts to load, bake, or render this malformed font via stbtt_GetGlyphShape(), the parser will attempt to read past the end of the glyph data buffer, triggering the out-of-bounds read.

The identification of this vulnerability is CVE-2026-18497 since 07/31/2026. The exploitation is known to be easy. The attack may be initiated remotely. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 08/07/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Vendor

• Sean Barrett

Name

• nothings stb

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5
• 1.6
• 1.7
• 1.8
• 1.9
• 1.10
• 1.11
• 1.12
• 1.13
• 1.14
• 1.15
• 1.16
• 1.17
• 1.18
• 1.19
• 1.20
• 1.21
• 1.22
• 1.23
• 1.24
• 1.25
• 1.26

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CPE 2.2info

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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