Vulnerability in Phildev Ipfilter

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 filtered, which allows remote attackers to identify filtered ports by comparing TTLs.

Published 2002-08-12 · last modified 2026-06-16.

CVSS v2 metric

CVSS v2 base score 5.0 (Medium). Vector: AV:N/AC:L/Au:N/C:P/I:N/A:N. This CVE predates CVSS v3 and has no v3 score from NVD.

EPSS exploit prediction

EPSS: 0.022 (81.8th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 82nd percentile — 81.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.022 · newest: 0.022 · change: 0.000

Affected products

Phildev Ipfilter

Weakness classification (CWE)

CWE-203 — Observable Discrepancy

References

www.securityfocus.com/archive/1/265188 (Broken Link, Vendor Advisory, mailing-list, VDB Entry, Third Party Advisory)
www.securityfocus.com/bid/4403 (Exploit, VDB Entry, Third Party Advisory, vdb-entry, Broken Link, Vendor Advisory)
www.iss.net/security_center/static/8738.php (vdb-entry, Broken Link, Vendor Advisory)