CVE-2000-0333: tcpdump, Ethereal, and other sniffer packages allow remote attackers to cause a denial of service via malforme

This month

MEDIUM 5.0DOWNGRADEDOWNGRADE

CVE-2000-0333 is a medium-severity flaw (CVSS 5.0) affecting ethereal, tcpdump. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

tcpdump, Ethereal, and other sniffer packages allow remote attackers to cause a denial of service via malformed DNS packets in which a jump offset refers to itself, which causes tcpdump to enter an infinite loop while decompressing the packet.

Why this priority

EPSS top 5%: very likely to be exploited
Public exploit reference

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

Risk facts

CVSS score	5.0 (Medium)
EPSS exploit chance	7.6% (top 5%)
CISA exploited list	No
Published	1999-05-31
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: ethereal group · lbl

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

Am I affected?

Timeline

1999-05-31 04:00 UTCPublished CVE record published
2026-06-16 21:51 UTCUpdated Record last modified

ethereal group ethereal DOWNGRADE

Affected: 0.8.4 · 0.8.5 · 0.8.6

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.8.4

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 0.8.4 (Debian / Ubuntu)

apt-cache madison ethereal sudo apt install ethereal=<VERSION_BEFORE_0.8.4> sudo apt-mark hold ethereal

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

dnf --showduplicates list ethereal sudo dnf downgrade ethereal-<VERSION_BEFORE_0.8.4> sudo dnf versionlock add ethereal

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.

lbl tcpdump DOWNGRADE

Affected: 3.4 · 3.5a

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.4

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 3.4 (Debian / Ubuntu)

apt-cache madison tcpdump sudo apt install tcpdump=<VERSION_BEFORE_3.4> sudo apt-mark hold tcpdump

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

dnf --showduplicates list tcpdump sudo dnf downgrade tcpdump-<VERSION_BEFORE_3.4> sudo dnf versionlock add tcpdump

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.

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Exploit-DB: Ethereal 0.8.4/0.8.5/0.8.6 / tcpdump 3.4/3.5 alpha - DNS Decode (1)
Exploit-DB: Ethereal 0.8.4/0.8.5/0.8.6 / tcpdump 3.4/3.5 alpha - DNS Decode (2)

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-2000-0333?

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

Is CVE-2000-0333 being exploited?

CVE-2000-0333 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-2000-0333 affect?

CVE-2000-0333 affects ethereal, tcpdump. Severity is medium (CVSS 5.0). tcpdump, Ethereal, and other sniffer packages allow remote attackers to cause a denial of service via malformed DNS packets in which a jump offset refers to itself, which causes tcpdump to enter an infinite loop while decompressing the pack

How urgent is CVE-2000-0333?

Priority 46/100. EPSS top 5%: very likely to be exploited; Public exploit reference

Related CVEs

CVE-2010-1455 MEDIUM 4.3 DOWNGRADE DOWNGRADE The DOCSIS dissector in Wireshark 0.9.6 through 1.0.12 and 1.2.0 through 1.2.7 allows user-assisted remote att
CVE-2007-6121 MEDIUM 5.0 DOWNGRADE DOWNGRADE Wireshark (formerly Ethereal) 0.8.16 to 0.99.6 allows remote attackers to cause a denial of service (crash) vi
CVE-2007-6120 MEDIUM 5.0 DOWNGRADE DOWNGRADE The Bluetooth SDP dissector Wireshark (formerly Ethereal) 0.99.2 to 0.99.6 allows remote attackers to cause a
CVE-2007-6118 HIGH 7.8 DOWNGRADE DOWNGRADE The MEGACO dissector in Wireshark (formerly Ethereal) 0.9.14 to 0.99.6 allows remote attackers to cause a deni
CVE-2007-6111 HIGH 7.1 DOWNGRADE DOWNGRADE Multiple unspecified vulnerabilities in Wireshark (formerly Ethereal) allow remote attackers to cause a denial

References

← Back to latest CVEs