Bug 2538514 (CVE-2026-88806)

Summary: CVE-2026-88806 libX11: libX11: Heap-based buffer overflow via malicious X server
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in libX11. A heap-based buffer overflow vulnerability exists during the handling of XkbGetMap replies. A remote attacker, by operating a malicious X server, could exploit this flaw to potentially execute arbitrary code or cause a denial of service on the client system. User interaction is required for exploitation.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Bug Depends On: 2539102    
Bug Blocks:    

Description OSIDB Bzimport 2026-09-22 18:55:17 UTC
A malicious X server could exploit a buffer overflow in libX11 before 1.8.14 during handling of XkbGetMap overflowing the key_sym_map.