CVE-2002-0231: Buffer overflow in mIRC 5.91 and earlier allows a remote server to execute arbitrary code on the client via a

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HIGH 7.5DOWNGRADE

CVE-2002-0231 is a high-severity flaw (CVSS 7.5) affecting mirc. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Buffer overflow in mIRC 5.91 and earlier allows a remote server to execute arbitrary code on the client via a long nickname.

Why this priority

High severity
EPSS top 5%: very likely to be exploited
Public exploit reference

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

Risk facts

CVSS score	7.5 (High)
EPSS exploit chance	9.6% (top 5%)
CISA exploited list	No
Published	2002-05-16
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: khaled mardam-bey

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

Am I affected?

Timeline

2002-05-16 04:00 UTCPublished CVE record published
2026-06-16 21:57 UTCUpdated Record last modified

khaled mardam-bey mirc DOWNGRADE

Affected: 2.1a · 2.3a · 2.4 · 2.4a · 2.5a · 2.7a · 2.8c · 3.1

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.1a

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 2.1a (Debian / Ubuntu)

apt-cache madison mirc sudo apt install mirc=<VERSION_BEFORE_2.1a> sudo apt-mark hold mirc

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

dnf --showduplicates list mirc sudo dnf downgrade mirc-<VERSION_BEFORE_2.1a> sudo dnf versionlock add mirc

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: MIRC 2.x/3.x/4.x/5.x - Nick 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-2002-0231?

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

Is CVE-2002-0231 being exploited?

CVE-2002-0231 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-2002-0231 affect?

CVE-2002-0231 affects mirc. Severity is high (CVSS 7.5). Buffer overflow in mIRC 5.91 and earlier allows a remote server to execute arbitrary code on the client via a long nickname.

How urgent is CVE-2002-0231?

Priority 55/100. High severity; EPSS top 5%: very likely to be exploited; Public exploit reference

Related CVEs

CVE-2019-6453 HIGH 8.1 UPGRADE mIRC before 7.55 allows remote command execution by using argument injection through custom URI protocol handl
CVE-2011-5282 MEDIUM 5.3 UPGRADE mIRC prior to 7.22 has a message leak because chopping of outbound messages is mishandled.
CVE-2008-7314 HIGH 7.5 UPGRADE mIRC before 6.35 allows attackers to cause a denial of service (crash) via a long nickname.
CVE-2008-4449 HIGH 9.3 DOWNGRADE Stack-based buffer overflow in mIRC 6.34 allows remote attackers to execute arbitrary code via a long hostname
CVE-2007-4402 MEDIUM 6.8 DOWNGRADE Multiple unspecified scripts in mIRC allow user-assisted remote attackers to execute arbitrary code via the '|

References

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