Bug 2451414 (CVE-2026-34085)

Summary: CVE-2026-34085 fontconfig: Fontconfig: Security flaw allows arbitrary code execution or system crash
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: adudiak, crizzo, kaycoth, kshier, stcannon, teagle, yguenane
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in fontconfig. This vulnerability, an off-by-one error in how fontconfig handles font capabilities, could allow a local attacker to cause a one-byte out-of-bounds write. This issue may lead to a system crash, resulting in a Denial of Service (DoS), or potentially enable the attacker to execute unauthorized code.
Story Points: ---
Clone Of: Environment:
Last Closed: 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: 2451645, 2451646    
Bug Blocks:    

Description OSIDB Bzimport 2026-03-25 18:02:43 UTC
fontconfig before 2.17.1 has an off-by-one error in allocation during sfnt capability handling, leading to a one-byte out-of-bounds write, and potentially a crash or code execution. This is in FcFontCapabilities in fcfreetype.c.