CVE-2004-0679: The IP cloaking feature (cloak.c) in UnrealIRCd 3.2, and possibly other versions, uses a weak hashing scheme t

Routine

MEDIUM 5.0DOWNGRADE

CVE-2004-0679 is a medium-severity flaw (CVSS 5.0) affecting unrealircd. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The IP cloaking feature (cloak.c) in UnrealIRCd 3.2, and possibly other versions, uses a weak hashing scheme to hide IP addresses, which could allow remote attackers to use brute force methods to gain other user's IP addresses.

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	1.6% (top 25%)
CISA exploited list	No
Published	2004-08-06
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: unreal

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

Am I affected?

Timeline

2004-08-06 04:00 UTCPublished CVE record published
2026-06-16 22:06 UTCUpdated Record last modified

unreal unrealircd DOWNGRADE

Affected: 3.1.1 · 3.1.3 · 3.2 · 3.2_.0_beta_10

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.1.1

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 3.1.1 (Debian / Ubuntu)

apt-cache madison unrealircd sudo apt install unrealircd=<VERSION_BEFORE_3.1.1> sudo apt-mark hold unrealircd

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

dnf --showduplicates list unrealircd sudo dnf downgrade unrealircd-<VERSION_BEFORE_3.1.1> sudo dnf versionlock add unrealircd

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-2004-0679?

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

Is CVE-2004-0679 being exploited?

CVE-2004-0679 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-2004-0679 affect?

CVE-2004-0679 affects unrealircd. Severity is medium (CVSS 5.0). The IP cloaking feature (cloak.c) in UnrealIRCd 3.2, and possibly other versions, uses a weak hashing scheme to hide IP addresses, which could allow remote attackers to use brute force methods to gain other user's IP addresses.

How urgent is CVE-2004-0679?

Priority 36/100. No elevated risk signals yet.

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References

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