CVE-2004-2054: CRLF injection vulnerability in PhpBB 2.0.4 and 2.0.9 allows remote attackers to perform HTTP Response Splitti

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MEDIUM 5.0DOWNGRADE

CVE-2004-2054 is a medium-severity flaw (CVSS 5.0) affecting phpbb. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

CRLF injection vulnerability in PhpBB 2.0.4 and 2.0.9 allows remote attackers to perform HTTP Response Splitting attacks to modify expected HTML content from the server via (1) the mode parameter to privmsg.php or (2) the redirect parameter to login.php.

Why this priority

Public exploit reference

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

Risk facts

CVSS score	5.0 (Medium)
EPSS exploit chance	2.2% (top 17%)
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-2004-2054?

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

Is CVE-2004-2054 being exploited?

CVE-2004-2054 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-2004-2054 affect?

CVE-2004-2054 affects phpbb. Severity is medium (CVSS 5.0). CRLF injection vulnerability in PhpBB 2.0.4 and 2.0.9 allows remote attackers to perform HTTP Response Splitting attacks to modify expected HTML content from the server via (1) the mode parameter to privmsg.php or (2) the redirect parameter

How urgent is CVE-2004-2054?

Priority 43/100. Public exploit reference

Software pages

PHP vulnerabilities

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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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