CVE-2004-0189

CVE-2004-0189 is a high-severity vulnerability in Squid with a CVSS 2.0 base score of 7.5. Its EPSS exploit-prediction score of 14% places it in the 96th percentile, indicating an elevated likelihood of exploitation.

Key facts

Description

The "%xx" URL decoding function in Squid 2.5STABLE4 and earlier allows remote attackers to bypass url_regex ACLs via a URL with a NULL ("%00") character, which causes Squid to use only a portion of the requested URL when comparing it against the access control lists.

Frequently asked questions

What is CVE-2004-0189?
The "%xx" URL decoding function in Squid 2.5STABLE4 and earlier allows remote attackers to bypass url_regex ACLs via a URL with a NULL ("%00") character, which causes Squid to use only a portion of the requested URL when comparing it against the access control lists.
How severe is CVE-2004-0189?
CVE-2004-0189 has a CVSS 2.0 base score of 7.5, rated high severity.
Is CVE-2004-0189 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 14% (96th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2004-0189?
CVE-2004-0189 primarily affects Squid. In total, 7 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2004-0189?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2004-0189 published?
CVE-2004-0189 was published on 2004-03-15 and last updated on 2026-06-16.

References

Affected products (7)

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