CVE-2026-33870

This High severity HTTP Request Smuggling vulnerability was introduced in version 8.9.0, 9.0.1, 9.1.0, 9.2.0, 9.3.1, 9.4.0, 9.5.1, 10.0.2, 10.1.0, 10.2.0 of Confluence Data Center. This HTTP Request Smuggling vulnerability, with a CVSS Score of 7.5 and a CVSS Vector of CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N allows an unauthenticated attacker to expose assets in your environment susceptible to exploitation which has no impact to confidentiality, high impact to integrity, no impact to availability, and requires no user interaction. Atlassian recommends that Confluence Data Center customers upgrade to latest version, if you are unable to do so, upgrade your instance to one of the specified supported fixed versions: * Confluence Data Center 10.2: Upgrade to a release greater than or equal to 10.2.10 * Confluence Data Center 9.2: Upgrade to a release greater than or equal to 9.2.19 See the release notes (https://confluence.atlassian.com/doc/confluence-release-notes-327.html). You can download the latest version of Confluence Data Center from the download center (https://www.atlassian.com/software/confluence/download-archives). The National Vulnerability Database provides the following description for this vulnerability: Netty is an asynchronous, event-driven network application framework. In versions prior to 4.1.132.Final and 4.2.10.Final, Netty incorrectly parses quoted strings in HTTP/1.1 chunked transfer encoding extension values, enabling request smuggling attacks. Versions 4.1.132.Final and 4.2.10.Final fix the issue.

EPSS 0.03% · 8.4th percentile