CVE-2004-2065: DansGuardian 2.8 and earlier allows remote attackers to bypass the extension filtering rule via a hex encoded

This month

HIGH 7.5DOWNGRADE

CVE-2004-2065 is a high-severity flaw (CVSS 7.5) affecting dansguardian. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

DansGuardian 2.8 and earlier allows remote attackers to bypass the extension filtering rule via a hex encoded extension or . in the filename.

Why this priority

High severity

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

Risk facts

CVSS score	7.5 (High)
EPSS exploit chance	1.9% (top 20%)
CISA exploited list	No
Published	2004-12-31
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: daniel barron

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

daniel barron dansguardian DOWNGRADE

Affected: 2.2.4 · 2.2.5 · 2.2.6 · 2.2.7 · 2.2.7.1 · 2.2.8 · 2.2.9 · 2.2.9.1

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.2.4

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 2.2.4 (Debian / Ubuntu)

apt-cache madison dansguardian sudo apt install dansguardian=<VERSION_BEFORE_2.2.4> sudo apt-mark hold dansguardian

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

dnf --showduplicates list dansguardian sudo dnf downgrade dansguardian-<VERSION_BEFORE_2.2.4> sudo dnf versionlock add dansguardian

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-2004-2065?

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

Is CVE-2004-2065 being exploited?

CVE-2004-2065 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-2004-2065 affect?

CVE-2004-2065 affects dansguardian. Severity is high (CVSS 7.5). DansGuardian 2.8 and earlier allows remote attackers to bypass the extension filtering rule via a hex encoded extension or . in the filename.

How urgent is CVE-2004-2065?

Priority 46/100. High severity

Related CVEs

CVE-2004-2283 MEDIUM 5.0 DOWNGRADE Unknown vulnerability in DansGuardian before 2.6.1-13 allows remote attackers to bypass URL filters via a craf
CVE-2004-2282 MEDIUM 5.0 DOWNGRADE DansGuardian before 2.7.7-2 allows remote attackers to bypass URL filters via a ".." in the request.
CVE-2003-1506 MEDIUM 4.3 DOWNGRADE Cross-site scripting (XSS) vulnerability in dansguardian.pl in Adelix CensorNet 3.0 through 3.2 allows remote
CVE-2002-1599 HIGH 7.5 DOWNGRADE DansGuardian before 2.4.5-1 allows remote attackers to bypass content filtering rules via hex-encoded URLs.

References

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