PatchTheCVECVE-2004-0523: Multiple buffer overflows in krb5_aname_to_localname for MIT Kerberos 5 (krb5) 1.3.3 and earlier allow remote
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HIGH 10.0DOWNGRADEDOWNGRADEDOWNGRADE
CVE-2004-0523 is a high-severity flaw (CVSS 10.0) affecting kerberos, kerberos 5, propack. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
Multiple buffer overflows in krb5_aname_to_localname for MIT Kerberos 5 (krb5) 1.3.3 and earlier allow remote attackers to execute arbitrary code as root.
Why this priority
- Critical severity
- EPSS top 4%: very likely to be exploited
No fix is published yet: follow the downgrade or mitigation steps.
Risk facts
| CVSS score | 10.0 (High) |
| EPSS exploit chance | 11.7% (top 4%) |
| CISA exploited list | No |
| Published | 2004-08-18 |
| Last modified | 2026-06-16 |
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
mit kerberos DOWNGRADE
Affected: 1.0 · 1.0.8 · 1.2.2.beta1
Fixed in: no fixed release known
Safe to downgrade to: a release before 1.0
1. Check installed version
apt-cache policy kerberos || rpm -q kerberos || kerberos --version
2. No fixed release: DOWNGRADE to a release before 1.0 (Debian / Ubuntu)
apt-cache madison kerberos
sudo apt install kerberos=<VERSION_BEFORE_1.0>
sudo apt-mark hold kerberos
2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list kerberos
sudo dnf downgrade kerberos-<VERSION_BEFORE_1.0>
sudo dnf versionlock add kerberos
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.
mit kerberos 5 DOWNGRADE
Affected: 1.0 · 1.0.6 · 1.1 · 1.1.1 · 1.2 · 1.2 beta1 · 1.2 beta2 · 1.2.1
Fixed in: no fixed release known
Safe to downgrade to: a release before 1.0
1. Check installed version
apt-cache policy kerberos-5 || rpm -q kerberos-5 || kerberos-5 --version
2. No fixed release: DOWNGRADE to a release before 1.0 (Debian / Ubuntu)
apt-cache madison kerberos-5
sudo apt install kerberos-5=<VERSION_BEFORE_1.0>
sudo apt-mark hold kerberos-5
2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list kerberos-5
sudo dnf downgrade kerberos-5-<VERSION_BEFORE_1.0>
sudo dnf versionlock add kerberos-5
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.
sgi propack DOWNGRADE
Affected: 2.4 · 3.0
Fixed in: no fixed release known
Safe to downgrade to: a release before 2.4
1. Check installed version
apt-cache policy propack || rpm -q propack || propack --version
2. No fixed release: DOWNGRADE to a release before 2.4 (Debian / Ubuntu)
apt-cache madison propack
sudo apt install propack=<VERSION_BEFORE_2.4>
sudo apt-mark hold propack
2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list propack
sudo dnf downgrade propack-<VERSION_BEFORE_2.4>
sudo dnf versionlock add propack
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.
sun seam DOWNGRADE
Affected: 1.0 · 1.0.1 · 1.0.2
Fixed in: no fixed release known
Safe to downgrade to: a release before 1.0
1. Check installed version
apt-cache policy seam || rpm -q seam || seam --version
2. No fixed release: DOWNGRADE to a release before 1.0 (Debian / Ubuntu)
apt-cache madison seam
sudo apt install seam=<VERSION_BEFORE_1.0>
sudo apt-mark hold seam
2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list seam
sudo dnf downgrade seam-<VERSION_BEFORE_1.0>
sudo dnf versionlock add seam
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.
tinysofa tinysofa enterprise server DOWNGRADE
Affected: 1.0 · 1.0_u1
Fixed in: no fixed release known
Safe to downgrade to: a release before 1.0
1. Check installed version
apt-cache policy tinysofa-enterprise-server || rpm -q tinysofa-enterprise-server || tinysofa-enterprise-server --version
2. No fixed release: DOWNGRADE to a release before 1.0 (Debian / Ubuntu)
apt-cache madison tinysofa-enterprise-server
sudo apt install tinysofa-enterprise-server=<VERSION_BEFORE_1.0>
sudo apt-mark hold tinysofa-enterprise-server
2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list tinysofa-enterprise-server
sudo dnf downgrade tinysofa-enterprise-server-<VERSION_BEFORE_1.0>
sudo dnf versionlock add tinysofa-enterprise-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.
sun solaris MITIGATE
Affected: 8.0 · 9.0
Fixed in: no fixed release known
Safe to downgrade to: a release before 8.0
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
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-2004-0523?
kerberos: downgrade or apply the listed mitigation; kerberos 5: downgrade or apply the listed mitigation; propack: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.
Is CVE-2004-0523 being exploited?
CVE-2004-0523 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-2004-0523 affect?
CVE-2004-0523 affects kerberos, kerberos 5, propack. Severity is high (CVSS 10.0). Multiple buffer overflows in krb5_aname_to_localname for MIT Kerberos 5 (krb5) 1.3.3 and earlier allow remote attackers to execute arbitrary code as root.
How urgent is CVE-2004-0523?
Priority 59/100. Critical severity; EPSS top 4%: very likely to be exploited
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