CVE-2004-1312: A bug in the HTML parser in a certain Microsoft HTML library, as used in various third party products, may all

This week

HIGH 10.0WATCHLISTDOWNGRADEDOWNGRADE

CVE-2004-1312 is a high-severity flaw (CVSS 10.0) affecting mailessentials, mailsecurity. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A bug in the HTML parser in a certain Microsoft HTML library, as used in various third party products, may allow remote attackers to cause a denial of service via certain strings, as reported in GFI MailEssentials for Exchange 9 and 10, and GFI MailSecurity for Exchange 8, which causes emails to remain in IIS or Exchange mail queues.

Why this priority

Critical severity
On your watchlist

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

Risk facts

CVSS score	10.0 (High)
EPSS exploit chance	2.5% (top 15%)
CISA exploited list	No
Published	2005-01-03
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: gfi

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

Am I affected?

Timeline

2005-01-03 05:00 UTCPublished CVE record published
2026-06-16 22:07 UTCUpdated Record last modified

gfi mailessentials DOWNGRADE

Affected: 9.0 · 10.0 · 10.1

Fixed in: no fixed release known

Safe to downgrade to: a release before 9.0

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 9.0 (Debian / Ubuntu)

apt-cache madison mailessentials sudo apt install mailessentials=<VERSION_BEFORE_9.0> sudo apt-mark hold mailessentials

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

dnf --showduplicates list mailessentials sudo dnf downgrade mailessentials-<VERSION_BEFORE_9.0> sudo dnf versionlock add mailessentials

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.

gfi mailsecurity DOWNGRADE

Affected: 8.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 8.0

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 8.0 (Debian / Ubuntu)

apt-cache madison mailsecurity sudo apt install mailsecurity=<VERSION_BEFORE_8.0> sudo apt-mark hold mailsecurity

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

dnf --showduplicates list mailsecurity sudo dnf downgrade mailsecurity-<VERSION_BEFORE_8.0> sudo dnf versionlock add mailsecurity

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-2004-1312?

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

Is CVE-2004-1312 being exploited?

CVE-2004-1312 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-2004-1312 affect?

CVE-2004-1312 affects mailessentials, mailsecurity. Severity is high (CVSS 10.0). A bug in the HTML parser in a certain Microsoft HTML library, as used in various third party products, may allow remote attackers to cause a denial of service via certain strings, as reported in GFI MailEssentials for Exchange 9 and 10, and

How urgent is CVE-2004-1312?

Priority 61/100. Critical severity; On your watchlist

Related CVEs

CVE-2025-34491 HIGH 8.8 UPGRADE GFI MailEssentials prior to version 21.8 is vulnerable to a .NET deserialization issue
CVE-2025-34490 MEDIUM 6.5 UPGRADE GFI MailEssentials prior to version 21.8 is vulnerable to an XML External Entity (XXE) issue
CVE-2025-34489 HIGH 7.8 UPGRADE GFI MailEssentials prior to version 21.8 is vulnerable to a local privilege escalation issue

References

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