Description
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).
Published: 2026-11-12
Score: 7.5 High
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

No analysis available yet.

Remediation

Vendor Workaround

Disable the EAP-SIM submodule in the FreeRADIUS configuration if SIM-based authentication is not required: 1. Edit `/etc/raddb/mods-available/eap` (or `/etc/raddb/mods-enabled/eap`) and comment out or remove the `sim` configuration block within the `eap` module definition: ``` # sim { # } ``` 2. Restart the FreeRADIUS service to apply the changes: ``` systemctl restart radiusd ``` Warning: Restarting or reloading the FreeRADIUS service will temporarily interrupt active RADIUS authentication requests. Clients relying on EAP-SIM authentication will no longer be able to authenticate. Additionally, restrict RADIUS UDP traffic (ports 1812 and 1813) to trusted Network Access Server (NAS) IP addresses using firewall rules to limit exposure to untrusted networks.

Tracking

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Advisories

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History

Thu, 12 Nov 2026 16:30:00 +0000

Type Values Removed Values Added
Description 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).
Title Freeradius: stack-based buffer overflow via unbounded eap-sim identity length
First Time appeared Redhat
Redhat enterprise Linux
Redhat rhel Els
Weaknesses CWE-787
CPEs cpe:/a:redhat:enterprise_linux:10
cpe:/a:redhat:enterprise_linux:8
cpe:/a:redhat:enterprise_linux:9
cpe:/o:redhat:rhel_els:6
cpe:/o:redhat:rhel_els:7
Vendors & Products Redhat
Redhat enterprise Linux
Redhat rhel Els
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}


Subscriptions

Redhat Enterprise Linux Rhel Els
cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-11-12T16:21:48.973Z

Reserved: 2026-11-12T10:45:33.541Z

Link: CVE-2026-127029

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-11-12T17:17:42.970

Modified: 2026-11-12T17:17:43.107

Link: CVE-2026-127029

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses