How severe is CVE-2001-1155?

CVE-2001-1155 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2001-1155 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (79th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2001-1155?

CVE-2001-1155 affects Freebsd. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2001-1155?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2001-1155 published?

CVE-2001-1155 was published on 2001-08-23 and last updated on 2026-06-16.

CVE-2001-1155

CVE-2001-1155 is a critical-severity vulnerability in Freebsd with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-863.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 2% (79th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-863
Affected product: Freebsd
Published: 2001-08-23
Last modified: 2026-06-16

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.

Frequently asked questions

What is CVE-2001-1155?: 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.
How severe is CVE-2001-1155?: CVE-2001-1155 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2001-1155 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (79th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2001-1155?: CVE-2001-1155 affects Freebsd. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2001-1155?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2001-1155 published?: CVE-2001-1155 was published on 2001-08-23 and last updated on 2026-06-16.

References

Affected products (1)

cpe:2.3:o:freebsd:freebsd:*:*:*:*:*:*:*:*

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