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CVE-2001-1155

Critical Vulnerability: CVE-2001-1155 — freebsd — freebsd

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.

Thursday, April 16, 2026freebsdVulnios Threat Intelligence
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Executive Summary

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.

Why It Matters

CVE-2001-1155 is rated CRITICAL severity, requiring immediate attention from security teams.

CVSS Base Score: 9.8/10

Affected Technologies

Vendors: freebsd

Products: freebsd

🛡️What Defenders Should Check

  • Check if you are affected — Review your asset inventory for products listed in CVE-2001-1155.
  • Apply available patches — Visit vendor advisories for the latest security updates.
  • Monitor for exploitation — Check your SIEM/IDS logs for related indicators.

    • Use Vulnios to continuously monitor your exposure to CVE-2001-1155 and similar vulnerabilities.

    References & Sources

  • ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-01:56.tcp_wrappers.asc
  • http://www.osvdb.org/5454
  • ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-01:56.tcp_wrappers.asc
  • http://www.osvdb.org/5454

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    Affected Products

    freebsd

    Sources

    critical

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