CVE-2004-2503: INweb Mail Server 2.40 allows remote attackers to cause a denial of service (crash) via a large number of conn

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MEDIUM 5.0DOWNGRADE

CVE-2004-2503 is a medium-severity flaw (CVSS 5.0) affecting mail server. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

INweb Mail Server 2.40 allows remote attackers to cause a denial of service (crash) via a large number of connect/disconnect actions to the (1) POP3 and (2) SMTP services.

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	1.9% (top 21%)
CISA exploited list	No
Published	2004-12-31
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: inweb

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

Am I affected?

Timeline

2004-12-31 05:00 UTCPublished CVE record published
2026-06-16 22:09 UTCUpdated Record last modified

inweb mail server DOWNGRADE

Affected: 2.40

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.40

1. Check installed version

apt-cache policy mail-server || rpm -q mail-server || mail-server --version

2. No fixed release: DOWNGRADE to a release before 2.40 (Debian / Ubuntu)

apt-cache madison mail-server sudo apt install mail-server=<VERSION_BEFORE_2.40> sudo apt-mark hold mail-server

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

dnf --showduplicates list mail-server sudo dnf downgrade mail-server-<VERSION_BEFORE_2.40> sudo dnf versionlock add mail-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.

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-2004-2503?

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

Is CVE-2004-2503 being exploited?

CVE-2004-2503 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-2004-2503 affect?

CVE-2004-2503 affects mail server. Severity is medium (CVSS 5.0). INweb Mail Server 2.40 allows remote attackers to cause a denial of service (crash) via a large number of connect/disconnect actions to the (1) POP3 and (2) SMTP services.

How urgent is CVE-2004-2503?

Priority 42/100. Public exploit reference

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References

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