CVE-2006-2659: libs/comverp.c in Courier MTA before 0.53.2 allows attackers to cause a denial of service (CPU consumption) vi

Q: How do I fix CVE-2006-2659?

courier mta: upgrade to newer than 0.44.2. Exact commands for each OS are on this page.

Q: Is CVE-2006-2659 being exploited?

CVE-2006-2659 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2006-2659 affect?

CVE-2006-2659 affects courier mta. Severity is high (CVSS 7.8). libs/comverp.c in Courier MTA before 0.53.2 allows attackers to cause a denial of service (CPU consumption) via unknown vectors involving usernames that contain the "=" (equals) character, which is not properly handled during encoding.

This month

HIGH 7.8UPGRADE

CVE-2006-2659 is a high-severity flaw (CVSS 7.8) affecting courier mta. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

libs/comverp.c in Courier MTA before 0.53.2 allows attackers to cause a denial of service (CPU consumption) via unknown vectors involving usernames that contain the "=" (equals) character, which is not properly handled during encoding.

Why this priority

High severity

A fixed release or distro patch exists.

Risk facts

CVSS score	7.8 (High)
EPSS exploit chance	2.4% (top 16%)
CISA exploited list	No
Published	2006-05-30
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: double precision incorporated

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

Am I affected?

Timeline

2006-05-30 19:02 UTCPublished CVE record published
2026-06-16 22:25 UTCUpdated Record last modified

double precision incorporated courier mta UPGRADE

Affected: <= 0.44.2 · 0.37.3 · 0.38.1 · 0.40 · 0.43 · 0.43.1 · 0.43.2 · 0.44

Fixed in: newer than 0.44.2

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy courier-mta || rpm -q courier-mta || courier-mta --version

2. UPGRADE to newer than 0.44.2 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade courier-mta

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade courier-mta

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

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-2006-2659?

courier mta: upgrade to newer than 0.44.2. Exact commands for each OS are on this page.

Is CVE-2006-2659 being exploited?

CVE-2006-2659 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-2006-2659 affect?

CVE-2006-2659 affects courier mta. Severity is high (CVSS 7.8). libs/comverp.c in Courier MTA before 0.53.2 allows attackers to cause a denial of service (CPU consumption) via unknown vectors involving usernames that contain the "=" (equals) character, which is not properly handled during encoding.

How urgent is CVE-2006-2659?

Priority 48/100. High severity

Related CVEs

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CVE-2002-1311 MEDIUM 4.6 DOWNGRADE Courier sqwebmail before 0.40.0 does not quickly drop privileges after startup in certain cases, which could a
CVE-2002-0914 MEDIUM 5.0 DOWNGRADE Double Precision Courier e-mail MTA allows remote attackers to cause a denial of service (CPU consumption) via

References

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