CVE-2000-0239: Buffer overflow in the MERCUR WebView WebMail server allows remote attackers to cause a denial of service via

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MEDIUM 5.0DOWNGRADEDOWNGRADEDOWNGRADE

CVE-2000-0239 is a medium-severity flaw (CVSS 5.0) affecting mercur imap4 server, mercur mailserver, mercur pop3 server. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Buffer overflow in the MERCUR WebView WebMail server allows remote attackers to cause a denial of service via a long mail_user parameter in the GET request.

Why this priority

Public exploit reference

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

Risk facts

CVSS score	5.0 (Medium)
EPSS exploit chance	3.6% (top 11%)
CISA exploited list	No
Published	2000-03-15
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: atrium software

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

Am I affected?

Timeline

2000-03-15 05:00 UTCPublished CVE record published
2026-06-16 21:51 UTCUpdated Record last modified

atrium software mercur imap4 server DOWNGRADE

Affected: 3.20.01

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.20.01

1. Check installed version

apt-cache policy mercur-imap4-server || rpm -q mercur-imap4-server || mercur-imap4-server --version

2. No fixed release: DOWNGRADE to a release before 3.20.01 (Debian / Ubuntu)

apt-cache madison mercur-imap4-server sudo apt install mercur-imap4-server=<VERSION_BEFORE_3.20.01> sudo apt-mark hold mercur-imap4-server

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

dnf --showduplicates list mercur-imap4-server sudo dnf downgrade mercur-imap4-server-<VERSION_BEFORE_3.20.01> sudo dnf versionlock add mercur-imap4-server

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.

atrium software mercur mailserver DOWNGRADE

Affected: 3.2

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.2

1. Check installed version

apt-cache policy mercur-mailserver || rpm -q mercur-mailserver || mercur-mailserver --version

2. No fixed release: DOWNGRADE to a release before 3.2 (Debian / Ubuntu)

apt-cache madison mercur-mailserver sudo apt install mercur-mailserver=<VERSION_BEFORE_3.2> sudo apt-mark hold mercur-mailserver

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

dnf --showduplicates list mercur-mailserver sudo dnf downgrade mercur-mailserver-<VERSION_BEFORE_3.2> sudo dnf versionlock add mercur-mailserver

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.

atrium software mercur pop3 server DOWNGRADE

Affected: 3.20.01

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.20.01

1. Check installed version

apt-cache policy mercur-pop3-server || rpm -q mercur-pop3-server || mercur-pop3-server --version

2. No fixed release: DOWNGRADE to a release before 3.20.01 (Debian / Ubuntu)

apt-cache madison mercur-pop3-server sudo apt install mercur-pop3-server=<VERSION_BEFORE_3.20.01> sudo apt-mark hold mercur-pop3-server

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

dnf --showduplicates list mercur-pop3-server sudo dnf downgrade mercur-pop3-server-<VERSION_BEFORE_3.20.01> sudo dnf versionlock add mercur-pop3-server

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: Atrium Software Mercur WebView WebMail-Client 1.0 - 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-2000-0239?

mercur imap4 server: downgrade or apply the listed mitigation; mercur mailserver: downgrade or apply the listed mitigation; mercur pop3 server: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2000-0239 being exploited?

CVE-2000-0239 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-2000-0239 affect?

CVE-2000-0239 affects mercur imap4 server, mercur mailserver, mercur pop3 server. Severity is medium (CVSS 5.0). Buffer overflow in the MERCUR WebView WebMail server allows remote attackers to cause a denial of service via a long mail_user parameter in the GET request.

How urgent is CVE-2000-0239?

Priority 45/100. Public exploit reference

Related CVEs

CVE-2000-0198 MEDIUM 5.0 DOWNGRADE DOWNGRADE Buffer overflow in POP3 and IMAP servers in the MERCUR mail server suite allows remote attackers to cause a de

References

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