CVE-2026-42585

This High severity HTTP Request Smuggling vulnerability was introduced in versions 9.12.1, 9.16.0, 9.17.0, 10.0.0, 10.1.1, 10.2.0, 10.3.0, 10.4.0, 10.5.0, 10.6.0, 10.7.1, 11.0.0, 11.1.0, 11.2.0, and 11.3.0 of Jira Software Data Center and Server.   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 Jira Software Data Center and Server customers upgrade to latest version, if you are unable to do so, upgrade your instance to one of the specified supported fixed versions: * Jira Software Data Center 11.3: Upgrade to a release greater than or equal to 11.3.7 * Jira Software Data Center 10.3: Upgrade to a release greater than or equal to 10.3.22 * Jira Software Data Center 9.12: Upgrade to a release greater than or equal to 9.12.28 See the release notes ([https://www.atlassian.com/software/jira/download-archives]). You can download the latest version of Jira Software Data Center and Server from the download center ([https://www.atlassian.com/software/jira/download-archives]).   The National Vulnerability Database provides the following description for this vulnerability:   Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Netty incorrectly parses malformed Transfer-Encoding, enabling request smuggling attacks. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.  

EPSS 0.27% · 19.1th percentile