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No exploitation reportedFix available

CVE-2020-25097

No exploitation reported by the sources we read.

  • Published2021-03-19
  • WeaknessCWE-20 · CWE-444

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

An issue was discovered in Squid through 4.13 and 5.x through 5.0.4. Due to improper input validation, it allows a trusted client to perform HTTP Request Smuggling and access services otherwise forbidden by the security controls. This occurs for certain uri_whitespace configuration settings.

Timeline

dates in UTC
  1. 2021-03-1905:15CVE publishedNVD

Versions per branch

NVD
Fedoraproject fedora
BranchAffectedFixed in
32.x= 32no fix published
33.x= 33no fix published
34.x= 34no fix published
Squid-cache squid
BranchAffectedFixed in
5.0≥ 5.0.1, < 5.0.55.0.5
4.14≥ 2.0, < 4.144.14
Debian debian linux
BranchAffectedFixed in
10.0= 10.0no fix published

1 more product in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • libecapRocky Linux:8all versions · fixed in 0:1.0.1-2.module+el8.4.0+404+316a0dc5
  • libecapRed Hat:rhel_eus:8.2::appstreamall versions · fixed in 0:1.0.1-2.module+el8.1.0+4044+36416a77and 3 other packages
  • libecapRed Hat:rhel_eus:8.1::appstreamall versions · fixed in 0:1.0.1-2.module+el8.1.0+4044+36416a77and 3 other packages
  • libecapRed Hat:enterprise_linux:8::appstreamall versions · fixed in 0:1.0.1-2.module+el8.1.0+4044+36416a77and 3 other packages
  • libecapAlmaLinux:8all versions · fixed in 1.0.1-2.module_el8.6.0+2741+01592ae8and 1 other package
  • squidUbuntu:20.04:LTSall versions · fixed in 4.10-1ubuntu1.3
  • squidSUSE:OpenStack Cloud Crowbar 9all versions · fixed in 3.5.21-26.35.1
  • squidSUSE:OpenStack Cloud 9all versions · fixed in 3.5.21-26.35.1

60 more package ranges on OSV.dev

Vendor advisories

  • CVE-2020-25097 Red Hat Product Security117 products fixed · 4 known affected

    squid: improper input validation may allow a trusted client to perform HTTP request smuggling

    squid as a component of Red Hat Enterprise Linux 6 · squid.src as a component of Red Hat Enterprise Linux 6 · squid34 as a component of Red Hat Enterprise Linux 6 · +1 more

  • RHSA-2021:2025 Red Hat Product Security60 products fixed

    Red Hat Security Advisory: squid:4 security update

  • RHSA-2021:1979 Red Hat Product Security30 products fixed

    Red Hat Security Advisory: squid:4 security update

  • RHSA-2021:1135 Red Hat Product Security27 products fixed

    Red Hat Security Advisory: squid security update

Full record on NVD

Fix

  1. Vendor fix Red Hat Product Security RHSA-2021:2025 · 60 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 After installing this update, the squid service will be restarted automatically.
  2. Workaround from the vendor Red Hat Product Security RHSA-2021:2025 · 60 productsThis flaw can be mitigated by setting the `uri_whitespace` directive in squid.conf to either: ``` uri_whitespace deny ``` or ``` uri_whitespace encode ```
  3. No fix planned, says the vendor Red Hat Product Security CVE-2020-25097 · 4 productsOut of support scope

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • NVDCVSS 3.18.6read 2026-10-23
  • NVDCVSS 2.05read 2026-10-23
  • NVDweakness (CWE)CWE-20, CWE-444read 2026-10-23
  • FIRST EPSSEPSS score7.3 %2026-11-09
  • OSVaffected packages—

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
Published
2021-03-19
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2020-25097?

An issue was discovered in Squid through 4.13 and 5.x through 5.0.4. Due to improper input validation, it allows a trusted client to perform HTTP Request Smuggling and access services otherwise forbidden by the security controls. This occurs for certain uri_whitespace configuration settings.

Is CVE-2020-25097 actively exploited?

Active exploitation of CVE-2020-25097 has not been confirmed. Its EPSS score was 7.3% on 2026-11-09, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2020-25097?

CVE-2020-25097 has a CVSS v3 base score of 8.6 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N.

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