CVE-2026-61642Squid Request Smuggling in HTTP Transfer-Encoding
Updated under an hour ago ()
Does this affect you?
It affects squid-cache squid. Add what you run to find out whether that includes you.
EPSS puts the chance of exploitation in the next 30 days at 4.68%, higher than 92% of scored CVEs.
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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.
- CVSS
- 7.7 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N
- Weakness (CWE)
- CWE-444
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- 4.68% (percentile 92)
- Assigned by
- GitHub_M
- NVD analysis
- Awaiting Analysis
- Record last updated
- Oct 13, 2026
- First seen by InfoSec Signals
- Oct 13, 2026
Affected products
squid-cache squid squid_cache:squid (from the name) | from 3.3.0.1, < 7.6 | CNA record |
References
- https://github.com/squid-cache/squid/security/advisories/GHSA-537g-4gfh-w7m6x-refsource-confirm
- https://github.com/squid-cache/squid/pull/2427x-refsource-misc
- https://github.com/squid-cache/squid/pull/2431x-refsource-misc
- https://github.com/squid-cache/squid/commit/d06f48de8b8cc9a378cb91ecfe8e89b6e81696d2x-refsource-misc
- https://github.com/squid-cache/squid/commit/d808a7c825a70275113790471135c9c4d547ee51x-refsource-misc
- https://github.com/squid-cache/squid/releases/tag/SQUID_7_6x-refsource-misc
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.