CVE-2006-0800: Interpretation conflict in PostNuke 0.761 and earlier allows remote attackers to conduct cross-site scripting

Routine

LOW 2.6DOWNGRADE

CVE-2006-0800 is a low-severity flaw (CVSS 2.6) affecting postnuke. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Interpretation conflict in PostNuke 0.761 and earlier allows remote attackers to conduct cross-site scripting (XSS) attacks via HTML tags with a trailing "<" character, which is interpreted as a ">" character by some web browsers but bypasses the blacklist protection in (1) the pnVarCleanFromInput function in pnAPI.php, (2) the pnSecureInput function in pnAntiCracker.php, and (3) the htmltext parameter in an edituser operation to user.php.

Why this priority

Public exploit reference

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

Risk facts

CVSS score	2.6 (Low)
EPSS exploit chance	2.2% (top 18%)
CISA exploited list	No
Weakness	CWE-79
Published	2006-02-20
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: postnuke software foundation

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

Am I affected?

Timeline

2006-02-20 22:02 UTCPublished CVE record published
2026-06-16 22:21 UTCUpdated Record last modified

postnuke software foundation postnuke DOWNGRADE

Affected: 0.7 · 0.62 · 0.63 · 0.64 · 0.70 · 0.71 · 0.72 · 0.73

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.7

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 0.7 (Debian / Ubuntu)

apt-cache madison postnuke sudo apt install postnuke=<VERSION_BEFORE_0.7> sudo apt-mark hold postnuke

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

dnf --showduplicates list postnuke sudo dnf downgrade postnuke-<VERSION_BEFORE_0.7> sudo dnf versionlock add postnuke

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: PostNuke 0.6x/0.7x NS-Languages Module - 'language' 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-2006-0800?

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

Is CVE-2006-0800 being exploited?

CVE-2006-0800 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-2006-0800 affect?

CVE-2006-0800 affects postnuke. Severity is low (CVSS 2.6). Interpretation conflict in PostNuke 0.761 and earlier allows remote attackers to conduct cross-site scripting (XSS) attacks via HTML tags with a trailing "<" character, which is interpreted as a ">" character by some web browsers but bypass

How urgent is CVE-2006-0800?

Priority 35/100. Public exploit reference

Software pages

PHP vulnerabilities

Related CVEs

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CVE-2007-0385 HIGH 7.8 DOWNGRADE The faq section in PostNuke 0.764 allows remote attackers to obtain sensitive information (the full path) via
CVE-2007-0384 MEDIUM 5.1 DOWNGRADE Cross-site scripting (XSS) vulnerability in preview in the reviews section in PostNuke 0.764 allows remote att

References

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