CVE-2001-0738: LogLine function in klogd in sysklogd 1.3 in various Linux distributions allows an attacker to cause a denial

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MEDIUM 5.0WATCHLISTDOWNGRADEMITIGATE

CVE-2001-0738 is a medium-severity flaw (CVSS 5.0) affecting immunix, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

LogLine function in klogd in sysklogd 1.3 in various Linux distributions allows an attacker to cause a denial of service (hang) by causing null bytes to be placed in log messages.

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	2.6% (top 15%)
CISA exploited list	No
Published	2001-10-18
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: debian · immunix

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

Am I affected?

Timeline

2001-10-18 04:00 UTCPublished CVE record published
2026-06-16 21:54 UTCUpdated Record last modified

immunix immunix DOWNGRADE

Affected: 6.2 · 7.0 · 7.0_beta

Fixed in: no fixed release known

Safe to downgrade to: a release before 6.2

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 6.2 (Debian / Ubuntu)

apt-cache madison immunix sudo apt install immunix=<VERSION_BEFORE_6.2> sudo apt-mark hold immunix

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

dnf --showduplicates list immunix sudo dnf downgrade immunix-<VERSION_BEFORE_6.2> sudo dnf versionlock add immunix

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.

debian debian linux MITIGATE

Affected: 1.3 · 2.2

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.3

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.

Quick answers

How do I fix CVE-2001-0738?

immunix: downgrade or apply the listed mitigation; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2001-0738 being exploited?

CVE-2001-0738 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-2001-0738 affect?

CVE-2001-0738 affects immunix, debian linux. Severity is medium (CVSS 5.0). LogLine function in klogd in sysklogd 1.3 in various Linux distributions allows an attacker to cause a denial of service (hang) by causing null bytes to be placed in log messages.

How urgent is CVE-2001-0738?

Priority 44/100. On your watchlist

Software pages

Debian vulnerabilities

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References

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