CVE-2001-1155

Name: CVE-2001-1155
Creator: NVD / NIST
Published: 2001-08-23T04:00:00+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 2.03%

Last modified Jun 16, 2026

CVE-2001-1155 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. TCP Wrappers (tcp_wrappers) in FreeBSD 4.1.1 through 4.3 with the PARANOID ACL option enabled does not properly check the result of a reverse DNS lookup, which could allow remote attackers to bypass intended access restrictions via DNS spoofing.. EPSS estimates a 2.03% chance of exploitation in the next 30 days.

Description

TCP Wrappers (tcp_wrappers) in FreeBSD 4.1.1 through 4.3 with the PARANOID ACL option enabled does not properly check the result of a reverse DNS lookup, which could allow remote attackers to bypass intended access restrictions via DNS spoofing.

Metrics

CVSS 3.1

9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

2.03%

78.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-863

Affected Software

Vendor	Product	Versions
Freebsd	Freebsd	>= 4.1.1, <= 4.3

References

ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-01:56.tcp_wrappers.ascBroken Link, Patch, Vendor Advisory
http://www.osvdb.org/5454Broken Link
ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-01:56.tcp_wrappers.ascBroken Link, Patch, Vendor Advisory
http://www.osvdb.org/5454Broken Link

Timeline

Published: Aug 23, 2001
Last Modified: Jun 16, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2001-1155?

How severe is CVE-2001-1155?

CVE-2001-1155 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 2.03% probability of exploitation in the next 30 days.

How do I fix CVE-2001-1155?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2001-1155?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST