Bug 2572339 (CVE-2026-127029)

Summary: CVE-2026-127029 freeradius: Stack-based buffer overflow via unbounded EAP-SIM identity length
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: high    
Version: unspecifiedCC: rhel-process-autobot, security-response-team, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in freeradius's Extensible Authentication Protocol Method for Subscriber Identity Module (EAP-SIM) module. When handling authentication requests, the server copies a client-supplied identity into an internal structure without properly checking its length against a fixed-size buffer. An unauthenticated remote attacker can exploit this issue by sending specially crafted EAP-SIM messages, triggering a stack buffer overflow that crashes the service and results in a Denial of Service (DoS).
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2572353    
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Description OSIDB Bzimport 2026-11-12 11:33:36 UTC 
A flaw was found in freeradius's EAP-SIM module. The server copies the client-supplied EAP identity into an internal key-derivation structure without bounding its length against the destination field, and the resulting length is then used unchecked when deriving session keys, copying attacker-controlled data past the end of a fixed-size stack buffer. An unauthenticated client exchanging EAP-SIM messages with a server that has the module enabled can trigger this to crash the RADIUS server process.