CVE-2026-61642
published 2026-10-13CVE-2026-61642: Squid is a caching proxy for the Web. From 3.3.0.1 to before 7.6, due to an improper enforcement of behavioral workflow bug, Squid is vulnerable to a Request…
PriorityP356high7.7CVSS 3.1
AVNACLPRLUINSCCNIHAN
EPSS
2.22%
82.6th percentile
Squid is a caching proxy for the Web. From 3.3.0.1 to before 7.6, due to an improper enforcement of behavioral workflow bug, Squid is vulnerable to a Request Smuggling attack against HTTP/1.1 Transfer-Encoding. HTTP header parsing (`src/HttpHeader.cc`) accepted the bare` Transfer-Encoding:` identity form, which the HTTP specification prohibits because any transfer coding must be wrapped within chunked encoding. This problem allows a trusted client to perform an HTTP Request Smuggling attack when HTTP/1.1 is used, bypassing security mechanisms that may be in place between attacker and Squid. When there is an HTTP cache operating prior to the affected Squid, this Request Smuggling attack also allows the attacker to poison that web cache and store arbitrary malicious content at any URL for delivery to other clients' future requests. This issue is fixed in version 7.6.
Affected
5 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| squid-cache | squid | — | — |
| squid | squid | — | — |
| squid_4 | squid | — | — |
| ubuntu | squid | — | — |
| ubuntu | squid3 | — | — |
CVSS provenance
nvdv3.17.7HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N
vendor_redhat7.7HIGH
vendor_ubuntu7.5HIGH
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Ubuntu
Squid vulnerabilities
vendor_ubuntu·2026-10-20·CVSS 7.5
CVE-2026-47729 [HIGH] Squid vulnerabilities
Title: Squid vulnerabilities
Summary: Several security issues were fixed in Squid.
It was discovered that Squid incorrectly handled certain HTTP Transfer-
Encoding headers. An attacker could possibly use this issue to perform HTTP
request smuggling attacks, bypass security mechanisms, or poison web
caches. (CVE-2026-61642)
It was discovered that Squid incorrectly handled certain cache digest
replies, which could lead to a buffer overflow. A remote attacker could
possibly use this issue to cause Squid to crash, resulting in a denial of
service. This issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, and
Ubuntu 20.04 LTS. (CVE-2026-50012)
It was discovered that Squid incorrectly handled parsing certain FTP
directory listings. A remote attacker could possibly use this issue to
obtain
Red Hat
squid: squid: Request Smuggling in HTTP Transfer-Encoding
vendor_redhat·2026-09-12·CVSS 7.7
CVE-2026-61642 [HIGH] CWE-841 squid: squid: Request Smuggling in HTTP Transfer-Encoding
squid: squid: Request Smuggling in HTTP Transfer-Encoding
A flaw was found in Squid. Due to improper handling of HTTP/1.1 Transfer-Encoding headers, a trusted client can perform an HTTP request smuggling attack, interfering with how web requests are processed. This vulnerability allows an attacker to bypass intermediate security controls. When an HTTP cache operates in front of the affected Squid instance, the attacker can also poison that cache, causing it to store and deliver malicious content to other users.
Statement: This vulnerability is rated as having an Important severity because it allows network clients to bypass proxy security controls and poison shared web caches without requiring administrative privileges. In deployments where Squid acts as an intermediary or accelerator al
No detection rules found.
No public exploits indexed.
Bugzilla
CVE-2026-61642 squid: squid: Request Smuggling in HTTP Transfer-Encoding [fedora-all]
bugzilla·2026-10-09
CVE-2026-61642 [HIGH] CVE-2026-61642 squid: squid: Request Smuggling in HTTP Transfer-Encoding [fedora-all]
CVE-2026-61642 squid: squid: Request Smuggling in HTTP Transfer-Encoding [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
A request smuggling vulnerability was found in Squid. Due to improper enforcement of behavioral workflow when processing HTTP/1.1 Transfer-Encoding headers, a trusted client can perform an HTTP request smuggling attack. This can bypass security mechanisms between the attacker and Squid. When an HTTP cache operates prior to the affected Squid instance, this also allows cache poisoning, enabling the attacker to store arbitrary malicious content at any URL for delivery to other clients.
Bugzilla
CVE-2026-61642 squid: squid: Request Smuggling in HTTP Transfer-Encoding
bugzilla·2026-10-09
CVE-2026-61642 [HIGH] CVE-2026-61642 squid: squid: Request Smuggling in HTTP Transfer-Encoding
CVE-2026-61642 squid: squid: Request Smuggling in HTTP Transfer-Encoding
A request smuggling vulnerability was found in Squid. Due to improper enforcement of behavioral workflow when processing HTTP/1.1 Transfer-Encoding headers, a trusted client can perform an HTTP request smuggling attack. This can bypass security mechanisms between the attacker and Squid. When an HTTP cache operates prior to the affected Squid instance, this also allows cache poisoning, enabling the attacker to store arbitrary malicious content at any URL for delivery to other clients.
Squid versions 3.3.0.1 through 7.5 are affected. The fix is available in version 7.6.
Bugzilla
CVE-2025-61642 mediawiki: MediaWiki: Cross-site Scripting (XSS) vulnerability via improper input neutralization [fedora-42]
bugzilla·2026-02-03
CVE-2025-61642 [NONE] CVE-2025-61642 mediawiki: MediaWiki: Cross-site Scripting (XSS) vulnerability via improper input neutralization [fedora-42]
CVE-2025-61642 mediawiki: MediaWiki: Cross-site Scripting (XSS) vulnerability via improper input neutralization [fedora-42]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
Discussion:
This message is a reminder that Fedora Linux 42 is nearing its end of life.
Fedora will stop maintaining and issuing updates for Fedora Linux 42 on 2026-05-13.
It is Fedora's policy to close all bug reports from releases that are no longer
maintained. At that time this bug will be closed as EOL if it remains open with a
'version' of '42'.
Package Maintainer: If you wish for this bug to remain open because you
plan to fix it in a cur
https://github.com/squid-cache/squid/commit/d06f48de8b8cc9a378cb91ecfe8e89b6e81696d2https://github.com/squid-cache/squid/commit/d808a7c825a70275113790471135c9c4d547ee51https://github.com/squid-cache/squid/pull/2427https://github.com/squid-cache/squid/pull/2431https://github.com/squid-cache/squid/releases/tag/SQUID_7_6https://github.com/squid-cache/squid/security/advisories/GHSA-537g-4gfh-w7m6
2026-10-13
Published