# CVE-2026-61642: Squid Request Smuggling in HTTP Transfer-Encoding CVE-2026-61642 is fixed in 9 products on 1 platform, first by DEBIAN-CVE-2026-61642, released September 17, 2026. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2026-61642 - Priority: High - CVSS: 7.7 (Important) - EPSS: 0.0204 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Sep 28, 2026 - Weakness: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') - Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-61642 ## Description 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. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | squid Debian 13.5 (trixie) | 6.13-2+deb13u4 | [DEBIAN-CVE-2026-61642](https://patchblox.com/security/data/fix/linux/debian-cve-2026-61642.md) | Sep 17, 2026 | | Linux | squid Debian 14 | 7.6-1 | [DEBIAN-CVE-2026-61642](https://patchblox.com/security/data/fix/linux/debian-cve-2026-61642.md) | Sep 17, 2026 | | Linux | squid Ubuntu 18.04.6 LTS (bionic) | 3.5.27-1ubuntu1.14+esm6 | [squid 3.5.27-1ubuntu1.14+esm6](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-squid-3.5.27-1ubuntu1.14-esm6.md) | Oct 24, 2026 | | Linux | squid Ubuntu 20.04 LTS (focal) | 4.10-1ubuntu1.13+esm3 | [squid 4.10-1ubuntu1.13+esm3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-squid-4.10-1ubuntu1.13-esm3.md) | Oct 24, 2026 | | Linux | squid Ubuntu 22.04.1 LTS (jammy) | 5.9-0ubuntu0.22.04.8 | [squid 5.9-0ubuntu0.22.04.8](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-squid-5.9-0ubuntu0.22.04.8.md) | Oct 24, 2026 | | Linux | squid Ubuntu 24.04.5 LTS (noble) | 6.14-0ubuntu0.24.04.5 | [squid 6.14-0ubuntu0.24.04.5](https://patchblox.com/security/data/fix/linux/ubuntu-noble-squid-6.14-0ubuntu0.24.04.5.md) | Oct 24, 2026 | | Linux | squid Ubuntu 26.04.1 LTS (resolute) | 7.7-0ubuntu0.26.04.2 | [squid 7.7-0ubuntu0.26.04.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-squid-7.7-0ubuntu0.26.04.2.md) | Nov 7, 2026 | | Linux | squid amzn 2023 | 7:6.13-1.amzn2023.0.6 | [ALAS2023-2026-3145](https://patchblox.com/security/data/fix/linux/alas2023-2026-3145.md) | Sep 28, 2026 | | Linux | squid-cgi Ubuntu 18.04.6 LTS (bionic) | 3.5.27-1ubuntu1.14+esm6 | [squid-cgi 3.5.27-1ubuntu1.14+esm6](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-squid-cgi-3.5.27-1ubuntu1.14-esm6.md) | Oct 24, 2026 | | Linux | squid-cgi Ubuntu 20.04 LTS (focal) | 4.10-1ubuntu1.13+esm3 | [squid-cgi 4.10-1ubuntu1.13+esm3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-squid-cgi-4.10-1ubuntu1.13-esm3.md) | Oct 24, 2026 | | Linux | squid-cgi Ubuntu 22.04.1 LTS (jammy) | 5.9-0ubuntu0.22.04.8 | [squid-cgi 5.9-0ubuntu0.22.04.8](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-squid-cgi-5.9-0ubuntu0.22.04.8.md) | Oct 24, 2026 | | Linux | squid-cgi Ubuntu 24.04.5 LTS (noble) | 6.14-0ubuntu0.24.04.5 | [squid-cgi 6.14-0ubuntu0.24.04.5](https://patchblox.com/security/data/fix/linux/ubuntu-noble-squid-cgi-6.14-0ubuntu0.24.04.5.md) | Oct 24, 2026 | | Linux | squid-common Ubuntu 18.04.6 LTS (bionic) | 3.5.27-1ubuntu1.14+esm6 | [squid-common 3.5.27-1ubuntu1.14+esm6](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-squid-common-3.5.27-1ubuntu1.14-esm6.md) | Oct 24, 2026 | | Linux | squid-common Ubuntu 20.04 LTS (focal) | 4.10-1ubuntu1.13+esm3 | [squid-common 4.10-1ubuntu1.13+esm3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-squid-common-4.10-1ubuntu1.13-esm3.md) | Oct 24, 2026 | | Linux | squid-common Ubuntu 22.04.1 LTS (jammy) | 5.9-0ubuntu0.22.04.8 | [squid-common 5.9-0ubuntu0.22.04.8](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-squid-common-5.9-0ubuntu0.22.04.8.md) | Oct 24, 2026 | | Linux | squid-common Ubuntu 24.04.5 LTS (noble) | 6.14-0ubuntu0.24.04.5 | [squid-common 6.14-0ubuntu0.24.04.5](https://patchblox.com/security/data/fix/linux/ubuntu-noble-squid-common-6.14-0ubuntu0.24.04.5.md) | Oct 24, 2026 | | Linux | squid-common Ubuntu 26.04.1 LTS (resolute) | 7.7-0ubuntu0.26.04.2 | [squid-common 7.7-0ubuntu0.26.04.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-squid-common-7.7-0ubuntu0.26.04.2.md) | Nov 7, 2026 | | Linux | squid-debuginfo amzn 2023 | 7:6.13-1.amzn2023.0.6 | [ALAS2023-2026-3145](https://patchblox.com/security/data/fix/linux/alas2023-2026-3145.md) | Sep 28, 2026 | | Linux | squid-debugsource amzn 2023 | 7:6.13-1.amzn2023.0.6 | [ALAS2023-2026-3145](https://patchblox.com/security/data/fix/linux/alas2023-2026-3145.md) | Sep 28, 2026 | | Linux | squid-openssl Ubuntu 22.04.1 LTS (jammy) | 5.9-0ubuntu0.22.04.8 | [squid-openssl 5.9-0ubuntu0.22.04.8](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-squid-openssl-5.9-0ubuntu0.22.04.8.md) | Oct 24, 2026 | | Linux | squid-openssl Ubuntu 24.04.5 LTS (noble) | 6.14-0ubuntu0.24.04.5 | [squid-openssl 6.14-0ubuntu0.24.04.5](https://patchblox.com/security/data/fix/linux/ubuntu-noble-squid-openssl-6.14-0ubuntu0.24.04.5.md) | Oct 24, 2026 | | Linux | squid-openssl Ubuntu 26.04.1 LTS (resolute) | 7.7-0ubuntu0.26.04.2 | [squid-openssl 7.7-0ubuntu0.26.04.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-squid-openssl-7.7-0ubuntu0.26.04.2.md) | Nov 7, 2026 | | Linux | squid-purge Ubuntu 18.04.6 LTS (bionic) | 3.5.27-1ubuntu1.14+esm6 | [squid-purge 3.5.27-1ubuntu1.14+esm6](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-squid-purge-3.5.27-1ubuntu1.14-esm6.md) | Oct 24, 2026 | | Linux | squid-purge Ubuntu 20.04 LTS (focal) | 4.10-1ubuntu1.13+esm3 | [squid-purge 4.10-1ubuntu1.13+esm3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-squid-purge-4.10-1ubuntu1.13-esm3.md) | Oct 24, 2026 | | Linux | squid-purge Ubuntu 22.04.1 LTS (jammy) | 5.9-0ubuntu0.22.04.8 | [squid-purge 5.9-0ubuntu0.22.04.8](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-squid-purge-5.9-0ubuntu0.22.04.8.md) | Oct 24, 2026 | | Linux | squid-purge Ubuntu 24.04.5 LTS (noble) | 6.14-0ubuntu0.24.04.5 | [squid-purge 6.14-0ubuntu0.24.04.5](https://patchblox.com/security/data/fix/linux/ubuntu-noble-squid-purge-6.14-0ubuntu0.24.04.5.md) | Oct 24, 2026 | | Linux | squid3 Ubuntu 18.04.6 LTS (bionic) | 3.5.27-1ubuntu1.14+esm6 | [squid3 3.5.27-1ubuntu1.14+esm6](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-squid3-3.5.27-1ubuntu1.14-esm6.md) | Oct 24, 2026 | | Linux | squidclient Ubuntu 18.04.6 LTS (bionic) | 3.5.27-1ubuntu1.14+esm6 | [squidclient 3.5.27-1ubuntu1.14+esm6](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-squidclient-3.5.27-1ubuntu1.14-esm6.md) | Oct 24, 2026 | | Linux | squidclient Ubuntu 20.04 LTS (focal) | 4.10-1ubuntu1.13+esm3 | [squidclient 4.10-1ubuntu1.13+esm3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-squidclient-4.10-1ubuntu1.13-esm3.md) | Oct 24, 2026 | | Linux | squidclient Ubuntu 22.04.1 LTS (jammy) | 5.9-0ubuntu0.22.04.8 | [squidclient 5.9-0ubuntu0.22.04.8](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-squidclient-5.9-0ubuntu0.22.04.8.md) | Oct 24, 2026 | | Linux | squidclient Ubuntu 24.04.5 LTS (noble) | 6.14-0ubuntu0.24.04.5 | [squidclient 6.14-0ubuntu0.24.04.5](https://patchblox.com/security/data/fix/linux/ubuntu-noble-squidclient-6.14-0ubuntu0.24.04.5.md) | Oct 24, 2026 | --- Data as of 2026-11-08T19:12:23Z UTC. 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