CVE-2017-9148: The TLS session cache in FreeRADIUS 2.1.1 through 2.1.7, 3.0.x before 3.0.14, 3.1.x before 2017-02-04, and 4.0

This week

CRITICAL 9.8REMOTEDOWNGRADE

CVE-2017-9148 is a critical-severity flaw (CVSS 9.8) affecting freeradius. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The TLS session cache in FreeRADIUS 2.1.1 through 2.1.7, 3.0.x before 3.0.14, 3.1.x before 2017-02-04, and 4.0.x before 2017-02-04 fails to reliably prevent resumption of an unauthenticated session, which allows remote attackers (such as malicious 802.1X supplicants) to bypass authentication via PEAP or TTLS.

Why this priority

Critical severity
EPSS top 10%: very likely to be exploited
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	3.9% (top 10%)
CISA exploited list	No
Weakness	CWE-287
Published	2017-05-29
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: freeradius

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2017-05-29 17:29 UTCPublished CVE record published
2026-06-17 01:27 UTCUpdated Record last modified

freeradius freeradius DOWNGRADE

Affected: 2.1.1 · 2.1.2 · 2.1.3 · 2.1.4 · 2.1.6 · 2.1.7 · 3.0.0 · 3.0.1

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.1.1

1. Check installed version

apt-cache policy freeradius || rpm -q freeradius || freeradius --version

2. No fixed release: DOWNGRADE to a release before 2.1.1 (Debian / Ubuntu)

apt-cache madison freeradius sudo apt install freeradius=<VERSION_BEFORE_2.1.1> sudo apt-mark hold freeradius

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list freeradius sudo dnf downgrade freeradius-<VERSION_BEFORE_2.1.1> sudo dnf versionlock add freeradius

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2017-9148?

freeradius: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2017-9148 being exploited?

CVE-2017-9148 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2017-9148 affect?

CVE-2017-9148 affects freeradius. Severity is critical (CVSS 9.8). The TLS session cache in FreeRADIUS 2.1.1 through 2.1.7, 3.0.x before 3.0.14, 3.1.x before 2017-02-04, and 4.0.x before 2017-02-04 fails to reliably prevent resumption of an unauthenticated session, which allows remote attackers (such as ma

How urgent is CVE-2017-9148?

Priority 62/100. Critical severity; EPSS top 10%: very likely to be exploited; Remotely exploitable, no login, no user action

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References

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