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NVD / CVE Program· CNA mitre

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…

HighCVSS 7.5 · v2.0—Proof of concept Fix available

Noroxi assessment

Priority: Monitor (action score 34/100)

  • Public proof-of-concept code exists (Exploit-DB); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 13.8% (FIRST EPSS); higher than 96.5% of all records.
  • No special conditions are required; it is repeatable.
  • Fixed version: squid (Debian:12) 2.5.5-1; squid (Debian:3.0) 2.4.6-2woody2; squid (Red Hat:enterprise_linux:3::as) 7:2.5.STABLE3-5.3E.

Low priority for now. Upgrade to squid (Debian:12) 2.5.5-1; squid (Debian:3.0) 2.4.6-2woody2; squid (Red Hat:enterprise_linux:3::as) 7:2.5.STABLE3-5.3E or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

Published
Mar 15, 2004
Updated
Jun 16, 2026
EPSS
13.8% · 96th percentile
CWE
—

Report tools

JSON

Action score

34

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
4 / 30 · 13.8%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • Proof of concept exists, no weaponized module
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

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  • when exploit code appears or is weaponized
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  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
squidsquid

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • squid squid2.0_patch2
  • squid squid2.1_patch2
  • squid squid2.3_stable5
  • squid squid2.4
  • squid squid2.4_stable7
  • squid squid2.5_stable3
  • squid squid2.5_stable4

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12squidbefore 2.5.5-12.5.5-1
Debian:3.0squidbefore 2.4.6-2woody22.4.6-2woody2
Red Hat:enterprise_linux:3::assquidbefore 7:2.5.STABLE3-5.3E7:2.5.STABLE3-5.3E
Red Hat:enterprise_linux:3::assquid-debuginfobefore 7:2.5.STABLE3-5.3E7:2.5.STABLE3-5.3E

Same product

squid: all records

Other highest-scoring records for the same primary product.

  • CVE-2009-0478Squid 2.7 to 2.7.STABLE5, 3.0 to 3.0.STABLE12, and 3.1 to 3.1.0.4 allows remote attackers to cause a denial of service via an HTTP request…
    42Plan
  • CVE-2005-0194Squid 2.5, when processing the configuration file, parses empty Access Control Lists (ACLs), including proxy_auth ACLs without defined auth…
    42Plan
  • CVE-2005-0241The httpProcessReplyHeader function in http.c for Squid 2.5-STABLE7 and earlier does not properly set the debug context when it is handling…
    41Plan

Published before and after this one in the same product

  • ← EarlierCVE-2002-0715Jul 26, 2002 · Vulnerability in Squid before 2.4.STABLE6 related to proxy authentication credentials may allow remote web sites to obtain the user's proxy…
    21Monitor
  • ← EarlierCVE-2002-2414Dec 31, 2002 · Opera 6.0.3, when using Squid 2.4 for HTTPS proxying, does not properly handle when accepting a non-global certificate authority (CA)…
    17Monitor
  • Later →CVE-2004-0832Nov 3, 2004 · The (1) ntlm_fetch_string and (2) ntlm_get_string functions in Squid 2.5.6 and earlier, with NTLM authentication enabled, allow remote…
    23Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:squid2.5.5-1 · Debian:12Package registry (OSV)
red hat:squid7:2.5.STABLE3-5.3E · Red Hat:enterprise_linux:3::asPackage registry (OSV)
red hat:squid-debuginfo7:2.5.STABLE3-5.3E · Red Hat:enterprise_linux:3::asPackage registry (OSV)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Exploit-DB entry ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Exploit-DB entryremote2004-03-01

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. First PoC-14 d
  2. Published
  3. TodayNov 15, 2026+8280 d

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • No special conditions are required; it is repeatable.

If successful

Confidentiality
P · data can be read
Integrity
P · data or configuration can be modified
Availability
P · the service can be disrupted
Attack complexity
Low
Confidentiality impact
P
Integrity impact
P
Availability impact
P

Weakness class (CWE)

—

CVSS vector

AV:N/AC:L/Au:N/C:P/I:P/A:P

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

References

Show all references (12 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records