CVE-2025-66939: Cross Site Scripting vulnerability in 66biolinks by AltumCode v.61.0.1 allows an attacker to execute arbitrary

Routine

MEDIUM 5.4DOWNGRADE

CVE-2025-66939 is a medium-severity flaw (CVSS 5.4) affecting 66biolinks. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Cross Site Scripting vulnerability in 66biolinks by AltumCode v.61.0.1 allows an attacker to execute arbitrary code via a crafted favicon file

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	None
User interaction	Required
EPSS exploit chance	0.3% (top 82%)
CISA exploited list	No
Weakness	CWE-79
Published	2026-01-12
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: altumcode

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

Am I affected?

Timeline

2026-01-12 16:16 UTCPublished CVE record published
2026-06-17 09:57 UTCUpdated Record last modified

altumcode 66biolinks DOWNGRADE

Affected: 61.0.1

Fixed in: no fixed release known

Safe to downgrade to: a release before 61.0.1

1. Check installed version

apt-cache policy 66biolinks || rpm -q 66biolinks || 66biolinks --version

2. No fixed release: DOWNGRADE to a release before 61.0.1 (Debian / Ubuntu)

apt-cache madison 66biolinks sudo apt install 66biolinks=<VERSION_BEFORE_61.0.1> sudo apt-mark hold 66biolinks

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

dnf --showduplicates list 66biolinks sudo dnf downgrade 66biolinks-<VERSION_BEFORE_61.0.1> sudo dnf versionlock add 66biolinks

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-2025-66939?

66biolinks: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2025-66939 being exploited?

CVE-2025-66939 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-2025-66939 affect?

CVE-2025-66939 affects 66biolinks. Severity is medium (CVSS 5.4). Cross Site Scripting vulnerability in 66biolinks by AltumCode v.61.0.1 allows an attacker to execute arbitrary code via a crafted favicon file

How urgent is CVE-2025-66939?

Priority 29/100. Public exploit reference

Related CVEs

CVE-2025-69602 CRITICAL 9.1 DOWNGRADE A session fixation vulnerability exists in 66biolinks v62.0.0 by AltumCode, where the application does not reg
CVE-2025-69601 MEDIUM 6.5 DOWNGRADE A directory traversal (Zip Slip) vulnerability exists in the “Static Sites” feature of 66biolinks v44.0.0 by A

References

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