CVE-2003-0864: Buffer overflow in m_join in channel.c for IRCnet IRCD 2.10.x to 2.10.3p3 allows remote attackers to cause a d

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MEDIUM 5.0DOWNGRADE

CVE-2003-0864 is a medium-severity flaw (CVSS 5.0) affecting ircnet ircd. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Buffer overflow in m_join in channel.c for IRCnet IRCD 2.10.x to 2.10.3p3 allows remote attackers to cause a denial of service.

Why this priority

EPSS top 9%: very likely to be exploited
Public exploit reference

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

Risk facts

CVSS score	5.0 (Medium)
EPSS exploit chance	4.2% (top 9%)
CISA exploited list	No
Published	2003-11-17
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: ircnet

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

Am I affected?

Timeline

2003-11-17 05:00 UTCPublished CVE record published
2026-06-16 22:03 UTCUpdated Record last modified

ircnet ircnet ircd DOWNGRADE

Affected: 2.10 · 2.10.3_p3

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.10

1. Check installed version

apt-cache policy ircnet-ircd || rpm -q ircnet-ircd || ircnet-ircd --version

2. No fixed release: DOWNGRADE to a release before 2.10 (Debian / Ubuntu)

apt-cache madison ircnet-ircd sudo apt install ircnet-ircd=<VERSION_BEFORE_2.10> sudo apt-mark hold ircnet-ircd

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

dnf --showduplicates list ircnet-ircd sudo dnf downgrade ircnet-ircd-<VERSION_BEFORE_2.10> sudo dnf versionlock add ircnet-ircd

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.

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Exploit-DB: IRCnet IRCD 2.10 - Local Buffer Overflow

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-2003-0864?

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

Is CVE-2003-0864 being exploited?

CVE-2003-0864 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-2003-0864 affect?

CVE-2003-0864 affects ircnet ircd. Severity is medium (CVSS 5.0). Buffer overflow in m_join in channel.c for IRCnet IRCD 2.10.x to 2.10.3p3 allows remote attackers to cause a denial of service.

How urgent is CVE-2003-0864?

Priority 45/100. EPSS top 9%: very likely to be exploited; Public exploit reference

References

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