High · CVSS 7.5CVE-2026-127030

Freeradius: stack buffer overflow via unchecked eap-fast sessionticket lengthCVE-2026-127030

Answer in brief

CVE-2026-127030 records a High severity (CVSS 7.5) vulnerability in Freeradius: stack buffer overflow via unchecked eap-fast sessionticket length. The current sources do not mark it as known exploited. The current feed maps Red Hat/freeradius (generic), Red Hat/freeradius:3.0/freeradius (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Nov 12, 2026Updated Nov 12, 2026Source checked Nov 12, 2026First seen by HOL Nov 12, 2026Material review Nov 12, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 7.5
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Not reported

Why this deserves its current priority

CVSS is 7.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Red Hat/freeradius (generic), Red Hat/freeradius:3.0/freeradius (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Red Hat/freeradiusgeneric	*	Not reported
Red Hat/freeradius:3.0/freeradiusgeneric	*	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Red Hat/freeradius, Red Hat/freeradius:3.0/freeradius.
Review the reported fix. Source-reported workaround: Disable the EAP-FAST submodule in the FreeRADIUS configuration, or restrict incoming RADIUS traffic to trusted network access points. 1. Disable EAP-FAST: In `/etc/raddb/mods-available/eap` (or `/etc/raddb/eap.conf`), comment out the `fast` section within the `eap` configuration block and verify that `default_eap_type` is not set to `fast`. 2. Apply configuration changes: ``` systemctl restart radiusd ``` 3. Limit network exposure: Restrict UDP port 1812 to authorized Network Access Server (NAS) clients using firewalld: ``` firewall-cmd --permanent --zone=internal --add-source=<TRUSTED_IP_OR_SUBNET> firewall-cmd --permanent --zone=internal --add-port=1812/udp firewall-cmd --reload ``` Caveats: Disabling EAP-FAST prevents authentication for any network clients that rely exclusively on EAP-FAST. Restricting firewall rules will block traffic from unlisted authenticator sources. Warning: Restarting or reloading the radiusd service will temporarily disrupt active RADIUS authentication processing.

Evidence timeline and material changes

Published upstream
Nov 12, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Nov 12, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Nov 12, 2026

Sources and claim methodology

Upstream source description

A flaw was found in freeradius. An improper length validation in the EAP-FAST module allows a stack-based buffer overflow during session ticket processing. A remote, unauthenticated attacker can exploit this flaw by sending a specially crafted handshake request, causing the server process to crash and resulting in a Denial of Service (DoS).

Quoted source text, attributed separately from HOL analysis.

Freeradius: stack-based buffer overflow via unbounded eap-sim identity lengthSame red hat/freeradius package

Affected scope and exposure questions

The current feed maps Red Hat/freeradius (generic), Red Hat/freeradius:3.0/freeradius (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Red Hat/freeradiusgeneric	*	Not reported
Red Hat/freeradius:3.0/freeradiusgeneric	*	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Red Hat/freeradius, Red Hat/freeradius:3.0/freeradius.

Review the reported fix. Source-reported workaround: Disable the EAP-FAST submodule in the FreeRADIUS configuration, or restrict incoming RADIUS traffic to trusted network access points. 1. Disable EAP-FAST: In `/etc/raddb/mods-available/eap` (or `/etc/raddb/eap.conf`), comment out the `fast` section within the `eap` configuration block and verify that `default_eap_type` is not set to `fast`. 2. Apply configuration changes: ``` systemctl restart radiusd ``` 3. Limit network exposure: Restrict UDP port 1812 to authorized Network Access Server (NAS) clients using firewalld: ``` firewall-cmd --permanent --zone=internal --add-source=<TRUSTED_IP_OR_SUBNET> firewall-cmd --permanent --zone=internal --add-port=1812/udp firewall-cmd --reload ``` Caveats: Disabling EAP-FAST prevents authentication for any network clients that rely exclusively on EAP-FAST. Restricting firewall rules will block traffic from unlisted authenticator sources. Warning: Restarting or reloading the radiusd service will temporarily disrupt active RADIUS authentication processing.

Sources and claim methodology

Upstream source description

Quoted source text, attributed separately from HOL analysis.

Freeradius: stack buffer overflow via unchecked eap-fast sessionticket lengthCVE-2026-127030

Key facts

Why this deserves its current priority

Affected scope and exposure questions

Recommended response

Evidence timeline and material changes

Sources and claim methodology

Related CVEs

Freeradius: stack buffer overflow via unchecked eap-fast sessionticket lengthCVE-2026-127030

Key facts

Why this deserves its current priority

Affected scope and exposure questions

Recommended response

Evidence timeline and material changes

Sources and claim methodology

Related CVEs