# CVE-2026-79515: nothings stb out-of-bounds read in TrueType glyph parsing

Source: https://junglewise.ai/threats/cve-2026-79515-nothings-stb-out-of-bounds-read-in-truetype-glyph-parsing  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-09. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-79515 · Severity: medium · CVSS 4.3 · Published 2026-09-09

stb is a widely-used single-header C library for font rendering and other media processing. An out-of-bounds memory read in its TrueType font parser allows an attacker to trigger a denial-of-service crash by providing a crafted font file with malformed glyph contours. Applications that load untrusted fonts without sandboxing could experience unexpected crashes or potential information leakage.

Technologies: [Nothings Stb](https://junglewise.ai/threats/technologies/stb). Vendors: [Nothings](https://junglewise.ai/threats/vendors/nothings).

## Quick answers

**Is CVE-2026-79515 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-79515 being exploited in the wild.

**How severe is CVE-2026-79515?** Medium severity, with a CVSS score of 4.3, published 9 September 2026.

**Which products and versions are affected?** Nothings Stb commit 31c1ad3 and prior.

**Is there a fix for CVE-2026-79515?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-79515 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-79515?** Check whether you run Nothings Stb at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is an out-of-bounds read (heap buffer over-read) in the stbtt__GetGlyphShapeTT function at stb_truetype.h line 1780. The root cause occurs when a contour's final vertex is an off-curve point: the code attempts to read vertices[off+n].type, which accesses one byte past the allocated n-element vertex array. The vulnerable code path is triggered via stbtt_GetGlyphShape when parsing a TrueType glyph containing a single contour with only an off-curve point. No authentication is required; an attacker simply provides a crafted TTF file. The impact is a crash due to memory access violation, resulting in denial of service. A patch has been identified in the upstream GitHub repository (nothings/stb issue #1962).

## Affected products

- nothings stb commit 31c1ad3 and prior

## Timeline

- 2026-06-06: disclosed: Issue reported on GitHub
- 2026-09-09: advisory: CVE-2026-79515 published on NVD

## References

- [https://github.com/nothings/stb/issues/1962](https://github.com/nothings/stb/issues/1962)
- [https://github.com/user-attachments/files/31364325/poc_truetype.c](https://github.com/user-attachments/files/31364325/poc_truetype.c)

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- [nothings stb integer overflow in hexwave_init](https://junglewise.ai/threats/cve-2026-102804-a-vulnerability-was-detected-in-nothings-stb-up-to)
- [stb out-of-bounds write in stbsp_vsnprintf](https://junglewise.ai/threats/cve-2026-79516-stb-out-of-bounds-write-in-stbsp-vsnprintf)