CVE-2024-5521: Two Cross-Site Scripting vulnerabilities have been discovered in Alkacon's OpenCMS affecting version 16, which

Routine

MEDIUM 6.4DOWNGRADE

CVE-2024-5521 is a medium-severity flaw (CVSS 6.4) affecting opencms. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Two Cross-Site Scripting vulnerabilities have been discovered in Alkacon's OpenCMS affecting version 16, which could allow a user having the roles of gallery editor or VFS resource manager will have the permission to upload images in the .svg format containing JavaScript code. The code will be executed the moment another user accesses the image.

Why this priority

No elevated risk signals yet

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

Risk facts

CVSS score	6.4 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.3% (top 82%)
CISA exploited list	No
Weakness	CWE-79
Published	2024-05-30
Last modified	2026-06-17

Publisher (CNA): Spanish National Cybersecurity Institute, S.A. (INCIBE) · Vendor: alkacon

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

Am I affected?

Timeline

2024-05-30 12:15 UTCPublished CVE record published
2026-06-17 08:16 UTCUpdated Record last modified

alkacon opencms DOWNGRADE

Affected: 16.0.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 16.0.0

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 16.0.0 (Debian / Ubuntu)

apt-cache madison opencms sudo apt install opencms=<VERSION_BEFORE_16.0.0> sudo apt-mark hold opencms

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

dnf --showduplicates list opencms sudo dnf downgrade opencms-<VERSION_BEFORE_16.0.0> sudo dnf versionlock add opencms

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-2024-5521?

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

Is CVE-2024-5521 being exploited?

CVE-2024-5521 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-2024-5521 affect?

CVE-2024-5521 affects opencms. Severity is medium (CVSS 6.4). Two Cross-Site Scripting vulnerabilities have been discovered in Alkacon's OpenCMS affecting version 16, which could allow a user having the roles of gallery editor or VFS resource manager will have the permission to upload images in the .s

How urgent is CVE-2024-5521?

Priority 27/100. No elevated risk signals yet.

Related CVEs

CVE-2024-41446 MEDIUM 5.4 DOWNGRADE A stored cross-site scripting (XSS) vulnerability in Alkacon OpenCMS v17.0 allows attackers to execute arbitra
CVE-2025-3317 MEDIUM 4.3 MITIGATE A vulnerability classified as problematic has been found in fumiao opencms up to a0fafa5cff58719e9b27c2a2eec20
CVE-2025-28099 MEDIUM 4.3 DOWNGRADE opencms V2.3 is vulnerable to Arbitrary file read in src/main/webapp/view/admin/document/dataPage.jsp,
CVE-2025-0708 LOW 3.5 DOWNGRADE A vulnerability was found in fumiao opencms 2.2
CVE-2024-5520 MEDIUM 6.4 DOWNGRADE Two Cross-Site Scripting vulnerabilities have been discovered in Alkacon's OpenCMS affecting version 16, which

References

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