Bug 2531287

Summary:	CVE-2026-79515 stb: stb: Denial of Service via crafted TTF file [fedora-all]
Product:	[Fedora] Fedora	Reporter:	Vladimir Vasilev <vvasilev>
Component:	stb	Assignee:	Ben Beasley <code>
Status:	CLOSED WONTFIX	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	rawhide	CC:	code, mhroncok
Target Milestone:	---	Keywords:	Security, SecurityTracking
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:	{"flaws": ["5cecea2a-4228-4b95-9f8f-41ceba0171e6"]}
Fixed In Version:		Doc Type:	---
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2026-09-10 07:41:43 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:
Bug Blocks:	2531156

Description Vladimir Vasilev 2026-09-10 06:26:51 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.

An out-of-bounds read in the stbtt_GetGlyphShape component of nothings stb commit 31c1ad3 allows attackers to cause a Denial of Service (DoS) via sending a crafted TTF file.

Comment 1 Ben Beasley 2026-09-10 07:41:43 UTC

Neither the CVE https://www.cve.org/CVERecord?id=CVE-2026-79515 nor the linked upstream issue https://github.com/nothings/stb/issues/1962 includes a patch.

Given that the stb_truetype library begins with the following prominent warning,

// =======================================================================
//
//    NO SECURITY GUARANTEE -- DO NOT USE THIS ON UNTRUSTED FONT FILES
//
// This library does no range checking of the offsets found in the file,
// meaning an attacker can use it to read arbitrary memory.
//
// =======================================================================

it’s certain that upstream would not consider this a valid bug.

For those reasons, I’m not interested in trying to develop a patch for this, either.

Given that there’s no patch and probably never will be one, it doesn’t seem useful to track this downstream.

Feel free to reopen this or open a PR if a proposed patch appears, but please understand that stb_truetype is expected to be absolutely riddled with problems like this when used outside of the applications for which it was designed.