Is CVE-2013-4123 in the CISA KEV catalog?

No. CVE-2013-4123 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2013-4123?

CVE-2013-4123 has a CVSS v2 base score of 5.0 (MEDIUM).

What is the EPSS score for CVE-2013-4123?

CVE-2013-4123 has an EPSS score of 80.45% (100th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2013-4123

MEDIUMEPSS 100th pctl

5.0

CVSS v2

NVD

Description

client_side_request.cc in Squid 3.2.x before 3.2.13 and 3.3.x before 3.3.8 allows remote attackers to cause a denial of service via a crafted port number in a HTTP Host header.

CWE-20Improper Input Validation

CVSS v2 Vector

No CVSS vector data available.

Exploit Intelligence

80.45%probability of exploitation in 30 days

100thpercentile

Very high risk: more likely to be exploited than 100% of all known CVEs.

References

http://lists.opensuse.org/opensuse-updates/2013-09/msg00024.html
http://secunia.com/advisories/54142
http://secunia.com/advisories/54834
http://www.squid-cache.org/Advisories/SQUID-2013_3.txt
http://www.squid-cache.org/Versions/v3/3.2/changesets/squid-3.2-11826.patch
http://www.squid-cache.org/Versions/v3/3.3/changesets/squid-3.3-12591.patch

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-29.