CVE-2020-13881: In support.c in pam_tacplus 1.3.8 through 1.5.1, the TACACS+ shared secret gets logged via syslog if the DEBUG

Q: How do I fix CVE-2020-13881?

pam tacplus: upgrade to newer than 1.5.1; 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.

Q: Is CVE-2020-13881 being exploited?

CVE-2020-13881 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2020-13881 affect?

CVE-2020-13881 affects pam tacplus, debian linux, ubuntu linux. Severity is high (CVSS 7.5). In support.c in pam_tacplus 1.3.8 through 1.5.1, the TACACS+ shared secret gets logged via syslog if the DEBUG loglevel and journald are used.

Q: How urgent is CVE-2020-13881?

Priority 56/100. High severity; Remotely exploitable, no login, no user action; On your watchlist

This month

HIGH 7.5REMOTEWATCHLISTUPGRADEMITIGATEMITIGATE

CVE-2020-13881 is a high-severity flaw (CVSS 7.5) affecting pam tacplus, debian linux, ubuntu linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

In support.c in pam_tacplus 1.3.8 through 1.5.1, the TACACS+ shared secret gets logged via syslog if the DEBUG loglevel and journald are used.

Why this priority

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

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.7% (top 23%)
CISA exploited list	No
Weakness	CWE-532
Published	2020-06-06
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: arista · canonical · debian · pam tacplus project

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

Am I affected?

Timeline

2020-06-06 19:15 UTCPublished CVE record published
2026-06-17 02:53 UTCUpdated Record last modified

pam tacplus project pam tacplus UPGRADE

Affected: >= 1.3.8 and <= 1.5.1

Fixed in: newer than 1.5.1

Safe to downgrade to: a release before 1.3.8

1. Check installed version

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

2. UPGRADE to newer than 1.5.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade pam-tacplus

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade pam-tacplus

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 1.3.8 (Debian / Ubuntu)

apt-cache madison pam-tacplus sudo apt install pam-tacplus=<VERSION_BEFORE_1.3.8> sudo apt-mark hold pam-tacplus

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list pam-tacplus sudo dnf downgrade pam-tacplus-<VERSION_BEFORE_1.3.8> sudo dnf versionlock add pam-tacplus

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: 16.04 · 18.04 · 20.04

Fixed in: no fixed release known

Safe to downgrade to: a release before 16.04

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.

arista cloudvision portal UPGRADE

Affected: < 2020.1.2

Fixed in: 2020.1.2

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy cloudvision-portal || rpm -q cloudvision-portal || cloudvision-portal --version

2. UPGRADE to 2020.1.2 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade cloudvision-portal

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade cloudvision-portal

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

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-2020-13881?

pam tacplus: upgrade to newer than 1.5.1; 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-2020-13881 being exploited?

CVE-2020-13881 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-2020-13881 affect?

CVE-2020-13881 affects pam tacplus, debian linux, ubuntu linux. Severity is high (CVSS 7.5). In support.c in pam_tacplus 1.3.8 through 1.5.1, the TACACS+ shared secret gets logged via syslog if the DEBUG loglevel and journald are used.

How urgent is CVE-2020-13881?

Priority 56/100. High severity; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Ubuntu vulnerabilities · Debian vulnerabilities

Related CVEs

CVE-2020-27743 CRITICAL 9.8 UPGRADE libtac in pam_tacplus through 1.5.1 lacks a check for a failure of RAND_bytes()/RAND_pseudo_bytes()
CVE-2016-20014 CRITICAL 9.8 UPGRADE In pam_tacplus.c in pam_tacplus before 1.4.1, pam_sm_acct_mgmt does not zero out the arep data structure.

References

← Back to latest CVEs