CVE-2025-67163: A stored cross-site scripting (XSS) vulnerability in Simple Machines Forum v2.1.6 allows attackers to execute

Routine

MEDIUM 6.1DOWNGRADE

CVE-2025-67163 is a medium-severity flaw (CVSS 6.1) affecting simple machines forum. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A stored cross-site scripting (XSS) vulnerability in Simple Machines Forum v2.1.6 allows attackers to execute arbitrary web scripts or HTML via injecting a crafted payload into the Forum Name parameter.

Why this priority

No elevated risk signals yet

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

Risk facts

CVSS score	6.1 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.3% (top 84%)
CISA exploited list	No
Weakness	CWE-20, CWE-79, CWE-83
Published	2025-12-18
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: simplemachines

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

Am I affected?

Timeline

2025-12-18 20:16 UTCPublished CVE record published
2026-06-17 09:57 UTCUpdated Record last modified

simplemachines simple machines forum DOWNGRADE

Affected: 2.1.6

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.1.6

1. Check installed version

apt-cache policy simple-machines-forum || rpm -q simple-machines-forum || simple-machines-forum --version

2. No fixed release: DOWNGRADE to a release before 2.1.6 (Debian / Ubuntu)

apt-cache madison simple-machines-forum sudo apt install simple-machines-forum=<VERSION_BEFORE_2.1.6> sudo apt-mark hold simple-machines-forum

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

dnf --showduplicates list simple-machines-forum sudo dnf downgrade simple-machines-forum-<VERSION_BEFORE_2.1.6> sudo dnf versionlock add simple-machines-forum

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-2025-67163?

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

Is CVE-2025-67163 being exploited?

CVE-2025-67163 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-2025-67163 affect?

CVE-2025-67163 affects simple machines forum. Severity is medium (CVSS 6.1). A stored cross-site scripting (XSS) vulnerability in Simple Machines Forum v2.1.6 allows attackers to execute arbitrary web scripts or HTML via injecting a crafted payload into the Forum Name parameter.

How urgent is CVE-2025-67163?

Priority 25/100. No elevated risk signals yet.

References

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