CVE-2025-56236: FormCms v0.5.5 contains a stored cross-site scripting (XSS) vulnerability in the avatar upload feature

Routine

MEDIUM 6.1UPGRADE

CVE-2025-56236 is a medium-severity flaw (CVSS 6.1) affecting formcms. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

FormCms v0.5.5 contains a stored cross-site scripting (XSS) vulnerability in the avatar upload feature. Authenticated users can upload .html files containing malicious JavaScript, which are accessible via a public URL. When a privileged user accesses the file, the script executes in their browser context.

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	6.1 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.2% (top 90%)
CISA exploited list	No
Weakness	CWE-79
Published	2025-08-28
Last modified	2026-09-26

Publisher (CNA): MITRE · Vendor: formcms

Last updated 2026-09-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2025-08-28 15:16 UTCPublished CVE record published
2026-09-26 00:10 UTCUpdated Record last modified

formcms formcms UPGRADE

Affected: >= 0.5.5 and < 0.5.7

Fixed in: 0.5.7

Safe to downgrade to: a release before 0.5.5

1. Check installed version

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

2. UPGRADE to 0.5.7 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade formcms

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 0.5.5 (Debian / Ubuntu)

apt-cache madison formcms sudo apt install formcms=<VERSION_BEFORE_0.5.5> sudo apt-mark hold formcms

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

dnf --showduplicates list formcms sudo dnf downgrade formcms-<VERSION_BEFORE_0.5.5> sudo dnf versionlock add formcms

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-2025-56236?

formcms: upgrade to 0.5.7. Exact commands for each OS are on this page.

Is CVE-2025-56236 being exploited?

CVE-2025-56236 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-2025-56236 affect?

CVE-2025-56236 affects formcms. Severity is medium (CVSS 6.1). FormCms v0.5.5 contains a stored cross-site scripting (XSS) vulnerability in the avatar upload feature. Authenticated users can upload .html files containing malicious JavaScript, which are accessible via a public URL. When a privileged use

How urgent is CVE-2025-56236?

Priority 29/100. Public exploit reference

Related CVEs

CVE-2025-55797 MEDIUM 6.5 DOWNGRADE An improper access control vulnerability in FormCms v0.5.4 in the /api/schemas/history/[schemaId] endpoint all

References

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