CVE-2003-0108: isakmp_sub_print in tcpdump 3.6 through 3.7.1 allows remote attackers to cause a denial of service (CPU consum

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MEDIUM 5.0DOWNGRADE

CVE-2003-0108 is a medium-severity flaw (CVSS 5.0) affecting tcpdump. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

isakmp_sub_print in tcpdump 3.6 through 3.7.1 allows remote attackers to cause a denial of service (CPU consumption) via a certain malformed ISAKMP packet to UDP port 500, which causes tcpdump to enter an infinite loop.

Why this priority

EPSS top 4%: 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	11.3% (top 4%)
CISA exploited list	No
Published	2003-03-07
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: lbl

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

Am I affected?

Timeline

2003-03-07 05:00 UTCPublished CVE record published
2026-06-16 22:01 UTCUpdated Record last modified

lbl tcpdump DOWNGRADE

Affected: 3.5.2 · 3.6.2 · 3.7 · 3.7.1

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.5.2

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 3.5.2 (Debian / Ubuntu)

apt-cache madison tcpdump sudo apt install tcpdump=<VERSION_BEFORE_3.5.2> sudo apt-mark hold tcpdump

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

dnf --showduplicates list tcpdump sudo dnf downgrade tcpdump-<VERSION_BEFORE_3.5.2> 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: TCPDump 3.x - Malformed ISAKMP Packet Denial of Service

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-2003-0108?

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

Is CVE-2003-0108 being exploited?

CVE-2003-0108 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-2003-0108 affect?

CVE-2003-0108 affects tcpdump. Severity is medium (CVSS 5.0). isakmp_sub_print in tcpdump 3.6 through 3.7.1 allows remote attackers to cause a denial of service (CPU consumption) via a certain malformed ISAKMP packet to UDP port 500, which causes tcpdump to enter an infinite loop.

How urgent is CVE-2003-0108?

Priority 46/100. EPSS top 4%: very likely to be exploited; Public exploit reference

Related CVEs

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CVE-1999-1024 HIGH 7.5 DOWNGRADE ip_print procedure in Tcpdump 3.4a allows remote attackers to cause a denial of service via a packet with a ze
CVE-2000-1026 HIGH 10.0 DOWNGRADE Multiple buffer overflows in LBNL tcpdump allow remote attackers to execute arbitrary commands.
CVE-2023-1801 MEDIUM 6.5 DOWNGRADE The SMB protocol decoder in tcpdump version 4.99.3 can perform an out-of-bounds write when decoding a crafted
CVE-2020-8037 HIGH 7.5 DOWNGRADE MITIGATE The ppp decapsulator in tcpdump 4.9.3 can be convinced to allocate a large amount of memory.

References

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