CVE-2002-0515: IPFilter 3.4.25 and earlier sets a different TTL when a port is being filtered than when it is not being filte

Q: How do I fix CVE-2002-0515?

ipfilter: upgrade to newer than 3.4.25. Exact commands for each OS are on this page.

Q: Is CVE-2002-0515 being exploited?

CVE-2002-0515 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2002-0515 affect?

CVE-2002-0515 affects ipfilter. Severity is medium (CVSS 5.0). IPFilter 3.4.25 and earlier sets a different TTL when a port is being filtered than when it is not being filtered, which allows remote attackers to identify filtered ports by comparing TTLs.

Q: How urgent is CVE-2002-0515?

Priority 43/100. Public exploit reference

This month

MEDIUM 5.0UPGRADE

CVE-2002-0515 is a medium-severity flaw (CVSS 5.0) affecting ipfilter. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

IPFilter 3.4.25 and earlier sets a different TTL when a port is being filtered than when it is not being filtered, which allows remote attackers to identify filtered ports by comparing TTLs.

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	5.0 (Medium)
EPSS exploit chance	2.2% (top 18%)
CISA exploited list	No
Weakness	CWE-203
Published	2002-08-12
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: phildev

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

Am I affected?

Timeline

2002-08-12 04:00 UTCPublished CVE record published
2026-06-16 21:57 UTCUpdated Record last modified

phildev ipfilter UPGRADE

Affected: <= 3.4.25

Fixed in: newer than 3.4.25

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to newer than 3.4.25 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade ipfilter

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade ipfilter

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

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-2002-0515?

ipfilter: upgrade to newer than 3.4.25. Exact commands for each OS are on this page.

Is CVE-2002-0515 being exploited?

CVE-2002-0515 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-2002-0515 affect?

CVE-2002-0515 affects ipfilter. Severity is medium (CVSS 5.0). IPFilter 3.4.25 and earlier sets a different TTL when a port is being filtered than when it is not being filtered, which allows remote attackers to identify filtered ports by comparing TTLs.

How urgent is CVE-2002-0515?

Priority 43/100. Public exploit reference

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References

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