CVE-2012-5903: Cross-site scripting (XSS) vulnerability in Simple Machines Forum (SMF) 2.0.2 allows remote attackers to injec

Routine

MEDIUM 4.3DOWNGRADE

CVE-2012-5903 is a medium-severity flaw (CVSS 4.3) affecting smf. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Cross-site scripting (XSS) vulnerability in Simple Machines Forum (SMF) 2.0.2 allows remote attackers to inject arbitrary web script or HTML via the scheduled parameter to index.php.

Why this priority

Public exploit reference

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

Risk facts

CVSS score	4.3 (Medium)
EPSS exploit chance	1.6% (top 24%)
CISA exploited list	No
Weakness	CWE-79
Published	2012-11-17
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: simple machines

Last updated 2026-06-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2012-11-17 21:55 UTCPublished CVE record published
2026-06-16 23:47 UTCUpdated Record last modified

simple machines smf DOWNGRADE

Affected: 2.0.2

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.0.2

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 2.0.2 (Debian / Ubuntu)

apt-cache madison smf sudo apt install smf=<VERSION_BEFORE_2.0.2> sudo apt-mark hold smf

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

dnf --showduplicates list smf sudo dnf downgrade smf-<VERSION_BEFORE_2.0.2> sudo dnf versionlock add smf

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.

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Exploit-DB: Simple Machines Forum (SMF) 2.0.2 - 'scheduled' Cross-Site Scripting

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-2012-5903?

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

Is CVE-2012-5903 being exploited?

CVE-2012-5903 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-2012-5903 affect?

CVE-2012-5903 affects smf. Severity is medium (CVSS 4.3). Cross-site scripting (XSS) vulnerability in Simple Machines Forum (SMF) 2.0.2 allows remote attackers to inject arbitrary web script or HTML via the scheduled parameter to index.php.

How urgent is CVE-2012-5903?

Priority 39/100. Public exploit reference

Software pages

PHP vulnerabilities

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References

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