CVE-2002-1675: Format string vulnerability in the Cio_PrintF function of cio_main.c in Unreal IRCd 3.1.1 allows remote attack

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MEDIUM 6.4DOWNGRADE

CVE-2002-1675 is a medium-severity flaw (CVSS 6.4) affecting unrealircd. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Format string vulnerability in the Cio_PrintF function of cio_main.c in Unreal IRCd 3.1.1 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via format string specifiers.

Why this priority

No elevated risk signals yet

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

Risk facts

CVSS score	6.4 (Medium)
EPSS exploit chance	2.7% (top 14%)
CISA exploited list	No
Published	2002-12-31
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

2002-12-31 05:00 UTCPublished CVE record published
2026-06-16 21:59 UTCUpdated Record last modified

unreal unrealircd DOWNGRADE

Affected: 3.1.1

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-2002-1675?

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

Is CVE-2002-1675 being exploited?

CVE-2002-1675 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-2002-1675 affect?

CVE-2002-1675 affects unrealircd. Severity is medium (CVSS 6.4). Format string vulnerability in the Cio_PrintF function of cio_main.c in Unreal IRCd 3.1.1 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via format string specifiers.

How urgent is CVE-2002-1675?

Priority 44/100. No elevated risk signals yet.

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References

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