CVE-2004-1809: Cross-site scripting (XSS) vulnerability in phpBB 2.0.6d and earlier allows remote attackers to inject arbitra

Routine

MEDIUM 4.3DOWNGRADE

CVE-2004-1809 is a medium-severity flaw (CVSS 4.3) affecting phpbb. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Cross-site scripting (XSS) vulnerability in phpBB 2.0.6d and earlier allows remote attackers to inject arbitrary web script or HTML via the (1) postdays parameter to viewtopic.php or (2) topicdays parameter to viewforum.php.

Why this priority

No elevated risk signals yet

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

Risk facts

CVSS score	4.3 (Medium)
EPSS exploit chance	1.4% (top 27%)
CISA exploited list	No
Published	2004-12-31
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: phpbb group

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

Am I affected?

Timeline

2004-12-31 05:00 UTCPublished CVE record published
2026-06-16 22:08 UTCUpdated Record last modified

phpbb group phpbb DOWNGRADE

Affected: 2.0.0 · 2.0.1 · 2.0.2 · 2.0.3 · 2.0.4 · 2.0.5 · 2.0.6 · 2.0.6c

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.0.0

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 2.0.0 (Debian / Ubuntu)

apt-cache madison phpbb sudo apt install phpbb=<VERSION_BEFORE_2.0.0> sudo apt-mark hold phpbb

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

dnf --showduplicates list phpbb sudo dnf downgrade phpbb-<VERSION_BEFORE_2.0.0> sudo dnf versionlock add phpbb

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-2004-1809?

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

Is CVE-2004-1809 being exploited?

CVE-2004-1809 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-2004-1809 affect?

CVE-2004-1809 affects phpbb. Severity is medium (CVSS 4.3). Cross-site scripting (XSS) vulnerability in phpBB 2.0.6d and earlier allows remote attackers to inject arbitrary web script or HTML via the (1) postdays parameter to viewtopic.php or (2) topicdays parameter to viewforum.php.

How urgent is CVE-2004-1809?

Priority 33/100. No elevated risk signals yet.

Software pages

PHP vulnerabilities

Related CVEs

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CVE-2025-70811 MEDIUM 4.3 DOWNGRADE Cross Site Request Forgery vulnerability in Phpbb phbb3 v.3.3.15 allows a local attacker to execute arbitrary
CVE-2025-70810 HIGH 8.8 DOWNGRADE Cross Site Request Forgery vulnerability in Phpbb phbb3 v.3.3.15 allows a local attacker to execute arbitrary
CVE-2023-5917 LOW 2.4 UPGRADE A vulnerability, which was classified as problematic, has been found in phpBB up to 3.3.10
CVE-2020-8226 MEDIUM 5.8 UPGRADE A vulnerability exists in phpBB <v3.2.10 and <v3.3.1 which allowed remote image dimensions check to be used to

References

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