CVE-2023-53891: Blackcat CMS 1.4 contains a stored cross-site scripting vulnerability that allows authenticated users to injec

Routine

MEDIUM 5.4DOWNGRADE

CVE-2023-53891 is a medium-severity flaw (CVSS 5.4) affecting blackcat cms. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Blackcat CMS 1.4 contains a stored cross-site scripting vulnerability that allows authenticated users to inject malicious scripts into page content. Attackers can insert JavaScript payloads in the page modification interface that execute when other users view the compromised page.

Why this priority

Public exploit reference

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

Risk facts

CVSS score	5.4 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	Required
EPSS exploit chance	0.2% (top 84%)
CISA exploited list	No
Weakness	CWE-79
Published	2025-12-15
Last modified	2026-06-17

Publisher (CNA): VulnCheck · Vendor: blackcat-cms

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

Am I affected?

Timeline

2025-12-15 21:15 UTCPublished CVE record published
2026-06-17 06:46 UTCUpdated Record last modified

blackcat-cms blackcat cms DOWNGRADE

Affected: 1.4

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.4

1. Check installed version

apt-cache policy blackcat-cms || rpm -q blackcat-cms || blackcat-cms --version

2. No fixed release: DOWNGRADE to a release before 1.4 (Debian / Ubuntu)

apt-cache madison blackcat-cms sudo apt install blackcat-cms=<VERSION_BEFORE_1.4> sudo apt-mark hold blackcat-cms

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

dnf --showduplicates list blackcat-cms sudo dnf downgrade blackcat-cms-<VERSION_BEFORE_1.4> sudo dnf versionlock add blackcat-cms

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-2023-53891?

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

Is CVE-2023-53891 being exploited?

CVE-2023-53891 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-2023-53891 affect?

CVE-2023-53891 affects blackcat cms. Severity is medium (CVSS 5.4). Blackcat CMS 1.4 contains a stored cross-site scripting vulnerability that allows authenticated users to inject malicious scripts into page content. Attackers can insert JavaScript payloads in the page modification interface that execute wh

How urgent is CVE-2023-53891?

Priority 28/100. Public exploit reference

Related CVEs

CVE-2023-53892 HIGH 7.2 DOWNGRADE Blackcat CMS 1.4 contains a remote code execution vulnerability that allows authenticated administrators to up

References

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