Bug 2521845

Summary: CVE-2026-18497 monado: nothings stb TrueType library: Heap Buffer Overflow via malformed TrueType Font files [fedora-all]
Product: [Fedora] Fedora Reporter: Vladimir Vasilev <vvasilev>
Component: monadoAssignee: XR SIG <xr-sig>
Status: CLOSED WONTFIX QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: rawhideCC: jonathansteffan, xr-sig
Target Milestone: ---Keywords: Security, SecurityTracking
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["cf81c879-dcda-47cb-9455-bbc5e862ae54"]}
Fixed In Version: Doc Type: ---
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2026-08-27 13:43:38 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 2521844    
Bug Blocks: 2512517    

Description Vladimir Vasilev 2026-08-24 12:42:30 UTC 
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

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.