CVE-2000-1203: Lotus Domino SMTP server 4.63 through 5.08 allows remote attackers to cause a denial of service (CPU consumpti

Routine

MEDIUM 5.0DOWNGRADE

CVE-2000-1203 is a medium-severity flaw (CVSS 5.0) affecting domino. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Lotus Domino SMTP server 4.63 through 5.08 allows remote attackers to cause a denial of service (CPU consumption) by forging an email message with the sender as bounce@[127.0.0.1] (localhost), which causes Domino to enter a mail loop.

Why this priority

No elevated risk signals yet

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

Risk facts

CVSS score	5.0 (Medium)
EPSS exploit chance	2.5% (top 15%)
CISA exploited list	No
Published	2001-08-20
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: lotus

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

Am I affected?

Timeline

2001-08-20 04:00 UTCPublished CVE record published
2026-06-16 21:53 UTCUpdated Record last modified

lotus domino DOWNGRADE

Affected: 4.6.1 · 4.6.3 · 4.6.4 · 5.0.1 · 5.0.2 · 5.0.3 · 5.0.4 · 5.0.5

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.6.1

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 4.6.1 (Debian / Ubuntu)

apt-cache madison domino sudo apt install domino=<VERSION_BEFORE_4.6.1> sudo apt-mark hold domino

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

dnf --showduplicates list domino sudo dnf downgrade domino-<VERSION_BEFORE_4.6.1> sudo dnf versionlock add domino

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-2000-1203?

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

Is CVE-2000-1203 being exploited?

CVE-2000-1203 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-2000-1203 affect?

CVE-2000-1203 affects domino. Severity is medium (CVSS 5.0). Lotus Domino SMTP server 4.63 through 5.08 allows remote attackers to cause a denial of service (CPU consumption) by forging an email message with the sender as bounce@[127.0.0.1] (localhost), which causes Domino to enter a mail loop.

How urgent is CVE-2000-1203?

Priority 39/100. No elevated risk signals yet.

Related CVEs

CVE-2000-1046 HIGH 10.0 DOWNGRADE Multiple buffer overflows in the ESMTP service of Lotus Domino 5.0.2c and earlier allow remote attackers to ca
CVE-2024-23562 MEDIUM 5.3 DOWNGRADE A security vulnerability in HCL Domino could allow disclosure of sensitive configuration information
CVE-2023-37539 HIGH 8.4 DOWNGRADE The Domino Catalog template is susceptible to a Stored Cross-Site Scripting (XSS) vulnerability
CVE-2023-37495 MEDIUM 5.9 UPGRADE Internet passwords stored in Person documents in the Domino® Directory created using the "Add Person" action o
CVE-2023-28010 MEDIUM 4.0 DOWNGRADE In some configuration scenarios, the Domino server host name can be exposed

References

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