Bug 2459982 (CVE-2026-6862)

Summary: CVE-2026-6862 efivar: efivar: Denial of Service due to stack overflow in device path node parsing
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: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in libefiboot, a component of efivar. The device path node parser in libefiboot fails to validate that each node's Length field is at least 4 bytes, which is the minimum size for an EFI (Extensible Firmware Interface) device path node header. A local user could exploit this vulnerability by providing a specially crafted device path node. This can lead to infinite recursion, causing stack exhaustion and a process crash, resulting in a denial of service (DoS).
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Bug Depends On: 2460590, 2460591, 2460589    
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Description OSIDB Bzimport 2026-04-21 05:10:49 UTC 
A stack overflow vulnerability was found in libefiboot (part of efivar). The device path node parser does not validate that each node Length field is >= 4 bytes (minimum EFI device path node header size) before recursing. A crafted node with Length < 4 causes infinite recursion in efi_loadopt_is_valid() -> efi_loadopt_optional_data_size(), leading to stack exhaustion and process crash.

Upstream: github.com/rhboot/efivar - no Issues tab or SECURITY.md available. This report serves as initial upstream notification.
Suggested fix: Add minimum length guard: if (dp->length < 4) return -1;