CVE-2021-21438: Agents are able to see linked FAQ articles without permissions (defined in FAQ Category)

Routine

LOW 3.5UPGRADEUPGRADE

CVE-2021-21438 is a low-severity flaw (CVSS 3.5) affecting faq, otrs. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Agents are able to see linked FAQ articles without permissions (defined in FAQ Category). This issue affects: FAQ version 6.0.29 and prior versions, OTRS version 7.0.24 and prior versions.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	3.5 (Low)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	Required
EPSS exploit chance	0.6% (top 50%)
CISA exploited list	No
Weakness	CWE-264, CWE-276
Published	2021-03-22
Last modified	2026-06-17

Publisher (CNA): OTRS AG · Vendor: otrs

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

Am I affected?

Timeline

2021-03-22 09:15 UTCPublished CVE record published
2026-06-17 03:35 UTCUpdated Record last modified

otrs faq UPGRADE

Affected: >= 6.0.0 and < 6.0.29

Fixed in: 6.0.29

Safe to downgrade to: a release before 6.0.0

1. Check installed version

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

2. UPGRADE to 6.0.29 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade faq

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade faq

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 6.0.0 (Debian / Ubuntu)

apt-cache madison faq sudo apt install faq=<VERSION_BEFORE_6.0.0> sudo apt-mark hold faq

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

dnf --showduplicates list faq sudo dnf downgrade faq-<VERSION_BEFORE_6.0.0> sudo dnf versionlock add faq

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.

otrs otrs UPGRADE

Affected: >= 7.0.0 and < 7.0.24

Fixed in: 7.0.24

Safe to downgrade to: a release before 7.0.0

1. Check installed version

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

2. UPGRADE to 7.0.24 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade otrs

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade otrs

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 7.0.0 (Debian / Ubuntu)

apt-cache madison otrs sudo apt install otrs=<VERSION_BEFORE_7.0.0> sudo apt-mark hold otrs

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

dnf --showduplicates list otrs sudo dnf downgrade otrs-<VERSION_BEFORE_7.0.0> sudo dnf versionlock add otrs

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-2021-21438?

faq: upgrade to 6.0.29; otrs: upgrade to 7.0.24. Exact commands for each OS are on this page.

Is CVE-2021-21438 being exploited?

CVE-2021-21438 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-2021-21438 affect?

CVE-2021-21438 affects faq, otrs. Severity is low (CVSS 3.5). Agents are able to see linked FAQ articles without permissions (defined in FAQ Category). This issue affects: FAQ version 6.0.29 and prior versions, OTRS version 7.0.24 and prior versions.

How urgent is CVE-2021-21438?

Priority 25/100. No elevated risk signals yet.

Related CVEs

CVE-2016-5843 CRITICAL 9.4 DOWNGRADE Multiple SQL injection vulnerabilities in the FAQ package 2.x before 2.3.6, 4.x before 4.0.5, and 5.x before 5
CVE-2013-2637 MEDIUM 6.1 UPGRADE UPGRADE A Cross-Site Scripting (XSS) Vulnerability exists in OTRS ITSM prior to 3.2.4, 3.1.8, and 3.0.7 and FAQ prior
CVE-2013-2625 MEDIUM 6.5 UPGRADE UPGRADE An Access Bypass issue exists in OTRS Help Desk before 3.2.4, 3.1.14, and 3.0.19, OTRS ITSM before 3.2.3, 3.1.
CVE-2012-1646 MEDIUM 4.3 DOWNGRADE Multiple cross-site scripting (XSS) vulnerabilities in the FAQ module 6.x-1.x before 6.x-1.13 and 7.x-1.x-rc1
CVE-2006-4008 HIGH 7.5 DOWNGRADE PHP remote file inclusion vulnerability in index.php in Knusperleicht Faq 1.0 allows remote attackers to execu

References

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