CVE-2021-24837: The Passster WordPress plugin before 3.5.5.8 does not escape the area parameter of its shortcode, which could

Q: How do I fix CVE-2021-24837?

passter: upgrade to 3.5.5.8. Exact commands for each OS are on this page.

Q: Is CVE-2021-24837 being exploited?

CVE-2021-24837 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-2021-24837 affect?

CVE-2021-24837 affects passter. Severity is medium (CVSS 5.4). The Passster WordPress plugin before 3.5.5.8 does not escape the area parameter of its shortcode, which could allow users with a role as low as Contributor to perform Cross-Site Scripting attacks.

Q: How urgent is CVE-2021-24837?

Priority 27/100. No elevated risk signals yet.

Routine

MEDIUM 5.4UPGRADE

CVE-2021-24837 is a medium-severity flaw (CVSS 5.4) affecting passter. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The Passster WordPress plugin before 3.5.5.8 does not escape the area parameter of its shortcode, which could allow users with a role as low as Contributor to perform Cross-Site Scripting attacks.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	5.4 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	Required
EPSS exploit chance	0.4% (top 67%)
CISA exploited list	No
Published	2023-01-23
Last modified	2026-06-17

Publisher (CNA): WPScan · Vendor: passster project

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

Am I affected?

Timeline

2023-01-23 15:15 UTCPublished CVE record published
2026-06-17 03:40 UTCUpdated Record last modified

passster project passter UPGRADE

Affected: < 3.5.5.8

Fixed in: 3.5.5.8

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 3.5.5.8 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade passter

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-2021-24837?

passter: upgrade to 3.5.5.8. Exact commands for each OS are on this page.

Is CVE-2021-24837 being exploited?

CVE-2021-24837 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-2021-24837 affect?

CVE-2021-24837 affects passter. Severity is medium (CVSS 5.4). The Passster WordPress plugin before 3.5.5.8 does not escape the area parameter of its shortcode, which could allow users with a role as low as Contributor to perform Cross-Site Scripting attacks.

How urgent is CVE-2021-24837?

Priority 27/100. No elevated risk signals yet.

Software pages

WordPress vulnerabilities

Related CVEs

CVE-2021-24881 HIGH 7.5 UPGRADE The Passster WordPress plugin before 3.5.5.9 does not properly check for password, as well as that the post to

References

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