CVE-2004-2479: Squid Web Proxy Cache 2.5 might allow remote attackers to obtain sensitive information via URLs containing inv

Routine

MEDIUM 5.0DOWNGRADE

CVE-2004-2479 is a medium-severity flaw (CVSS 5.0) affecting squid web proxy cache. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Squid Web Proxy Cache 2.5 might allow remote attackers to obtain sensitive information via URLs containing invalid hostnames that cause DNS operations to fail, which results in references to previously used error messages.

Why this priority

No elevated risk signals yet

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

Risk facts

CVSS score	5.0 (Medium)
EPSS exploit chance	2.1% (top 18%)
CISA exploited list	No
Published	2004-12-31
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: national science foundation

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 22:09 UTCUpdated Record last modified

national science foundation squid web proxy cache DOWNGRADE

Affected: 2.5_stable1 · 2.5_stable2 · 2.5_stable3 · 2.5_stable4 · 2.5_stable5 · 2.5_stable6 · 2.5_stable7

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.5_stable1

1. Check installed version

apt-cache policy squid-web-proxy-cache || rpm -q squid-web-proxy-cache || squid-web-proxy-cache --version

2. No fixed release: DOWNGRADE to a release before 2.5_stable1 (Debian / Ubuntu)

apt-cache madison squid-web-proxy-cache sudo apt install squid-web-proxy-cache=<VERSION_BEFORE_2.5_stable1> sudo apt-mark hold squid-web-proxy-cache

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

dnf --showduplicates list squid-web-proxy-cache sudo dnf downgrade squid-web-proxy-cache-<VERSION_BEFORE_2.5_stable1> sudo dnf versionlock add squid-web-proxy-cache

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-2004-2479?

squid web proxy cache: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2004-2479 being exploited?

CVE-2004-2479 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-2004-2479 affect?

CVE-2004-2479 affects squid web proxy cache. Severity is medium (CVSS 5.0). Squid Web Proxy Cache 2.5 might allow remote attackers to obtain sensitive information via URLs containing invalid hostnames that cause DNS operations to fail, which results in references to previously used error messages.

How urgent is CVE-2004-2479?

Priority 38/100. No elevated risk signals yet.

Software pages

Squid vulnerabilities

Related CVEs

CVE-2009-0801 MEDIUM 5.4 DOWNGRADE Squid, when transparent interception mode is enabled, uses the HTTP Host header to determine the remote endpoi
CVE-2007-6239 MEDIUM 5.0 DOWNGRADE The "cache update reply processing" functionality in Squid 2.x before 2.6.STABLE17 and Squid 3.0 allows remote
CVE-2004-2480 MEDIUM 5.0 DOWNGRADE Squid Web Proxy Cache 2.3.STABLE5 allows remote attackers to bypass security controls and access arbitrary web
CVE-2004-0541 HIGH 10.0 DOWNGRADE Buffer overflow in the ntlm_check_auth (NTLM authentication) function for Squid Web Proxy Cache 2.5.x and 3.x,

References

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