CVE-2015-9542: add_password in pam_radius_auth.c in pam_radius 1.4.0 does not correctly check the length of the input passwor

This month

HIGH 7.5REMOTEWATCHLISTDOWNGRADEMITIGATEMITIGATE

CVE-2015-9542 is a high-severity flaw (CVSS 7.5) affecting pam radius, debian linux, ubuntu linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

add_password in pam_radius_auth.c in pam_radius 1.4.0 does not correctly check the length of the input password, and is vulnerable to a stack-based buffer overflow during memcpy(). An attacker could send a crafted password to an application (loading the pam_radius library) and crash it. Arbitrary code execution might be possible, depending on the application, C library, compiler, and other factors.

Why this priority

High severity
Remotely exploitable, no login, no user action
On your watchlist

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

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	3.5% (top 11%)
CISA exploited list	No
Weakness	CWE-787
Published	2020-02-24
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: canonical · debian · freeradius

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

Am I affected?

Timeline

2020-02-24 15:15 UTCPublished CVE record published
2026-06-17 00:36 UTCUpdated Record last modified

freeradius pam radius DOWNGRADE

Affected: 1.4.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.4.0

1. Check installed version

apt-cache policy pam-radius || rpm -q pam-radius || pam-radius --version

2. No fixed release: DOWNGRADE to a release before 1.4.0 (Debian / Ubuntu)

apt-cache madison pam-radius sudo apt install pam-radius=<VERSION_BEFORE_1.4.0> sudo apt-mark hold pam-radius

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

dnf --showduplicates list pam-radius sudo dnf downgrade pam-radius-<VERSION_BEFORE_1.4.0> sudo dnf versionlock add pam-radius

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.

debian debian linux MITIGATE

Affected: 8.0 · 9.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 8.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

canonical ubuntu linux MITIGATE

Affected: 12.04 · 14.04 · 16.04 · 18.04 · 19.10

Fixed in: no fixed release known

Safe to downgrade to: a release before 12.04

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

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-2015-9542?

pam radius: downgrade or apply the listed mitigation; debian linux: mitigate or apply the listed mitigation; ubuntu linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2015-9542 being exploited?

CVE-2015-9542 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-2015-9542 affect?

CVE-2015-9542 affects pam radius, debian linux, ubuntu linux. Severity is high (CVSS 7.5). add_password in pam_radius_auth.c in pam_radius 1.4.0 does not correctly check the length of the input password, and is vulnerable to a stack-based buffer overflow during memcpy(). An attacker could send a crafted password to an application

How urgent is CVE-2015-9542?

Priority 59/100. High severity; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Ubuntu vulnerabilities · Debian vulnerabilities

References

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