PatchTheCVECVE-2003-0300: The IMAP Client for Sylpheed 0.8.11 allows remote malicious IMAP servers to cause a denial of service (crash)
45
This month
MEDIUM 5.0WATCHLISTDOWNGRADEDOWNGRADEDOWNGRADE
CVE-2003-0300 is a medium-severity flaw (CVSS 5.0) affecting outlook express, mozilla, mutt. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
The IMAP Client for Sylpheed 0.8.11 allows remote malicious IMAP servers to cause a denial of service (crash) via certain large literal size values that cause either integer signedness errors or integer overflow errors.
Why this priority
- On your watchlist
No fix is published yet: follow the downgrade or mitigation steps.
Risk facts
| CVSS score | 5.0 (Medium) |
| EPSS exploit chance | 3.4% (top 11%) |
| CISA exploited list | No |
| Published | 2003-06-16 |
| Last modified | 2026-06-16 |
Publisher (CNA): MITRE · Vendor: microsoft · mozilla · mutt · qualcomm · stuart parmenter · sylpheed
Last updated 2026-06-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
microsoft outlook express DOWNGRADE
Affected: 6.00.2800.1106
Fixed in: no fixed release known
Safe to downgrade to: a release before 6.00.2800.1106
1. Check installed version
apt-cache policy outlook-express || rpm -q outlook-express || outlook-express --version
2. No fixed release: DOWNGRADE to a release before 6.00.2800.1106 (Debian / Ubuntu)
apt-cache madison outlook-express
sudo apt install outlook-express=<VERSION_BEFORE_6.00.2800.1106>
sudo apt-mark hold outlook-express
2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list outlook-express
sudo dnf downgrade outlook-express-<VERSION_BEFORE_6.00.2800.1106>
sudo dnf versionlock add outlook-express
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.
mozilla mozilla DOWNGRADE
Affected: 1.3 · 1.4 alpha
Fixed in: no fixed release known
Safe to downgrade to: a release before 1.3
1. Check installed version
apt-cache policy mozilla || rpm -q mozilla || mozilla --version
2. No fixed release: DOWNGRADE to a release before 1.3 (Debian / Ubuntu)
apt-cache madison mozilla
sudo apt install mozilla=<VERSION_BEFORE_1.3>
sudo apt-mark hold mozilla
2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list mozilla
sudo dnf downgrade mozilla-<VERSION_BEFORE_1.3>
sudo dnf versionlock add mozilla
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.
mutt mutt DOWNGRADE
Affected: 1.4.1
Fixed in: no fixed release known
Safe to downgrade to: a release before 1.4.1
1. Check installed version
apt-cache policy mutt || rpm -q mutt || mutt --version
2. No fixed release: DOWNGRADE to a release before 1.4.1 (Debian / Ubuntu)
apt-cache madison mutt
sudo apt install mutt=<VERSION_BEFORE_1.4.1>
sudo apt-mark hold mutt
2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list mutt
sudo dnf downgrade mutt-<VERSION_BEFORE_1.4.1>
sudo dnf versionlock add mutt
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.
qualcomm eudora DOWNGRADE
Affected: 5.2.1
Fixed in: no fixed release known
Safe to downgrade to: a release before 5.2.1
1. Check installed version
apt-cache policy eudora || rpm -q eudora || eudora --version
2. No fixed release: DOWNGRADE to a release before 5.2.1 (Debian / Ubuntu)
apt-cache madison eudora
sudo apt install eudora=<VERSION_BEFORE_5.2.1>
sudo apt-mark hold eudora
2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list eudora
sudo dnf downgrade eudora-<VERSION_BEFORE_5.2.1>
sudo dnf versionlock add eudora
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.
stuart parmenter balsa DOWNGRADE
Affected: 2.0.10
Fixed in: no fixed release known
Safe to downgrade to: a release before 2.0.10
1. Check installed version
apt-cache policy balsa || rpm -q balsa || balsa --version
2. No fixed release: DOWNGRADE to a release before 2.0.10 (Debian / Ubuntu)
apt-cache madison balsa
sudo apt install balsa=<VERSION_BEFORE_2.0.10>
sudo apt-mark hold balsa
2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list balsa
sudo dnf downgrade balsa-<VERSION_BEFORE_2.0.10>
sudo dnf versionlock add balsa
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.
sylpheed sylpheed email client DOWNGRADE
Affected: 0.8.11
Fixed in: no fixed release known
Safe to downgrade to: a release before 0.8.11
1. Check installed version
apt-cache policy sylpheed-email-client || rpm -q sylpheed-email-client || sylpheed-email-client --version
2. No fixed release: DOWNGRADE to a release before 0.8.11 (Debian / Ubuntu)
apt-cache madison sylpheed-email-client
sudo apt install sylpheed-email-client=<VERSION_BEFORE_0.8.11>
sudo apt-mark hold sylpheed-email-client
2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list sylpheed-email-client
sudo dnf downgrade sylpheed-email-client-<VERSION_BEFORE_0.8.11>
sudo dnf versionlock add sylpheed-email-client
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.
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-2003-0300?
outlook express: downgrade or apply the listed mitigation; mozilla: downgrade or apply the listed mitigation; mutt: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.
Is CVE-2003-0300 being exploited?
CVE-2003-0300 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-2003-0300 affect?
CVE-2003-0300 affects outlook express, mozilla, mutt. Severity is medium (CVSS 5.0). The IMAP Client for Sylpheed 0.8.11 allows remote malicious IMAP servers to cause a denial of service (crash) via certain large literal size values that cause either integer signedness errors or integer overflow errors.
How urgent is CVE-2003-0300?
Priority 45/100. On your watchlist
Software pages
Outlook vulnerabilities · Qualcomm vulnerabilities
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