CVE-2002-0834: Buffer overflow in the ISIS dissector for Ethereal 0.9.5 and earlier allows remote attackers to cause a denial

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HIGH 7.5DOWNGRADE

CVE-2002-0834 is a high-severity flaw (CVSS 7.5) affecting ethereal. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Buffer overflow in the ISIS dissector for Ethereal 0.9.5 and earlier allows remote attackers to cause a denial of service or execute arbitrary code via malformed packets.

Why this priority

High severity

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

Risk facts

CVSS score	7.5 (High)
EPSS exploit chance	2.5% (top 15%)
CISA exploited list	No
Published	2002-09-24
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: ethereal group

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

Am I affected?

Timeline

2002-09-24 04:00 UTCPublished CVE record published
2026-06-16 21:58 UTCUpdated Record last modified

ethereal group ethereal DOWNGRADE

Affected: 0.8 · 0.8.18 · 0.9.1 · 0.9.2 · 0.9.3 · 0.9.4 · 0.9.5 · 0.9_.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.8

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 0.8 (Debian / Ubuntu)

apt-cache madison ethereal sudo apt install ethereal=<VERSION_BEFORE_0.8> 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> 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.

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-2002-0834?

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

Is CVE-2002-0834 being exploited?

CVE-2002-0834 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-2002-0834 affect?

CVE-2002-0834 affects ethereal. Severity is high (CVSS 7.5). Buffer overflow in the ISIS dissector for Ethereal 0.9.5 and earlier allows remote attackers to cause a denial of service or execute arbitrary code via malformed packets.

How urgent is CVE-2002-0834?

Priority 47/100. High severity

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References

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