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Fencer Vulns
high 8.6

CVE-2020-25097 json

An issue was discovered in Squid through 4.13 and 5.x through 5.0.4.

published 2021-03-19 5 y ago modified 2026-06-17 4 mo ago also EUVD-2020-17789

cvss
8.6
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
7.3%
EPSS 7.3% chance of exploitation in 30 days, percentile 94%
public exploits
0
none known

Summary

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.

Patch / fix

  • squid-cache squid 4.14, 5.0.5
  • squid Debian 14, Debian 13, Debian 12 4.13-8

debian advisories DEBIAN-CVE-2020-25097

  • squid Ubuntu 20.04 LTS 4.10-1ubuntu1.3
  • squid3 Ubuntu 16.04 LTS 3.5.12-1ubuntu7.16
  • squid3 Ubuntu 18.04 LTS 3.5.27-1ubuntu1.10

ubuntu advisories UBUNTU-CVE-2020-25097

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • libecap RHEL 8, RHEL 8.2 EUS, RHEL 8.1 EUS 1.0.1-2.module+el8.1.0+4044+36416a77
  • squid RHEL 8 7:4.11-4.module+el8.4.0+10676+a969168e.2
  • squid RHEL 7 7:3.5.20-17.el7_9.6
  • squid-sysvinit RHEL 7 7:3.5.20-17.el7_9.6
  • squid-migration-script RHEL 7 7:3.5.20-17.el7_9.6
  • squid RHEL 8.1 EUS 7:4.4-8.module+el8.1.0+10584+c769fd35.3
  • squid RHEL 8.2 EUS 7:4.4-8.module+el8.2.0+10583+6e4ac934.3

red hat advisories RHSA-2021:2025RHSA-2021:1979RHSA-2021:1135

  • squid SLES for SAP 12 SP4, SLES 12 SP4-LTSS, SLES 12 SP3-BCL +3 more 3.5.21-26.35.1
  • squid3 SLES 11 SP4-LTSS, SLE Point of Sale 11 SP3 3.1.23-8.16.37.18.1
  • squid SLES for SAP 15 SP1, SLES for SAP 15, SLES 15-LTSS +12 more 4.15-5.26.1
  • squid SLES for SAP 12 SP5, SLES 12 SP5 4.15-4.18.1

suse advisories SUSE-SU-2022:2392-1SUSE-SU-2022:14914-1SUSE-SU-2021:1961-1SUSE-SU-2021:1838-1

  • squid openSUSE Tumbleweed 4.16-1.5
  • squid openSUSE Leap 15.3 4.15-5.26.1
  • squid openSUSE Leap 15.2 4.15-lp152.2.9.1

opensuse advisories openSUSE-SU-2024:11403-1openSUSE-SU-2021:1961-1openSUSE-SU-2021:0879-1

  • libecap AlmaLinux 8 1.0.1-2.module_el8.6.0+2741+01592ae8

almalinux advisories ALSA-2021:1979

  • squid Rocky Linux 8 7:4.11-4.module+el8.4.0+404+316a0dc5.2
  • libecap Rocky Linux 8 1.0.1-2.module+el8.4.0+404+316a0dc5

rocky linux advisories RLSA-2021:1979

  • squid Alpine 3.12, Alpine 3.11, Alpine 3.10 4.14-r0
  • squid Alpine 3.24, Alpine 3.23, Alpine 3.22 +9 more 5.0.5-r0

alpine advisories ALPINE-CVE-2020-25097

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-25097 updated cvss 8.6

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

  • Red Hat Enterprise Linux 6 squid, squid34
    affected: workaround, no fix planned “This flaw can be mitigated by setting the `uri_whitespace` directive in squid.conf to either: ``` uri_whitespace deny ``` or ``` uri_whitespace encode ```”
  • Red Hat Enterprise Linux AppStream (v. 8) libecap 1.0.1-2.module+el8.1.0+4044+36416a77, squid 4.11-4.module+el8.4.0+10676+a969168e.2
    fixed: vendor fix “This flaw can be mitigated by setting the `uri_whitespace` directive in squid.conf to either: ``` uri_whitespace deny ``` or ``` uri_whitespace encode ```” RHSA-2021:1979
  • Red Hat Enterprise Linux AppStream EUS (v. 8.1) squid 4.4-8.module+el8.1.0+10584+c769fd35.3, libecap 1.0.1-2.module+el8.1.0+4044+36416a77 Red Hat Enterprise Linux AppStream EUS (v. 8.2) squid 4.4-8.module+el8.2.0+10583+6e4ac934.3, libecap 1.0.1-2.module+el8.1.0+4044+36416a77
    fixed: vendor fix “This flaw can be mitigated by setting the `uri_whitespace` directive in squid.conf to either: ``` uri_whitespace deny ``` or ``` uri_whitespace encode ```” RHSA-2021:2025
  • Red Hat Enterprise Linux Server (v. 7) squid 3.5.20-17.el7_9.6, squid-migration-script 3.5.20-17.el7_9.6 Red Hat Enterprise Linux Server Optional (v. 7) squid-sysvinit 3.5.20-17.el7_9.6 Red Hat Enterprise Linux Workstation (v. 7) squid 3.5.20-17.el7_9.6, squid-migration-script 3.5.20-17.el7_9.6 Red Hat Enterprise Linux Workstation Optional (v. 7) squid-sysvinit 3.5.20-17.el7_9.6
    fixed: vendor fix “This flaw can be mitigated by setting the `uri_whitespace` directive in squid.conf to either: ``` uri_whitespace deny ``` or ``` uri_whitespace encode ```” RHSA-2021:1135
  • Red Hat Enterprise Linux 9 squid
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

7.34% chance of exploitation in the next 30 days, higher than 94% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 8.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:P/I:N/A:N

Classification

Weakness
  • CWE-20 Improper Input Validation
  • CWE-444 Inconsistent Interpretation of HTTP Requests

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.