CVE-2026-55833

This High severity DoS (Denial of Service) vulnerability was introduced in versions 9.12.1, 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. This DoS (Denial of Service) 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:N/A:H allows an unauthenticated attacker to cause a resource to be unavailable for its intended users by temporarily or indefinitely disrupting services of a host connected to a network which has no impact to confidentiality, no impact to integrity, high impact to availability, and requires no user interaction. Atlassian recommends that Jira Software 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: * Jira Software Data Center 9.12: Upgrade to a release greater than or equal to 9.12.28 * Jira Software Data Center 10.3: Upgrade to a release greater than or equal to 10.3.24 * Jira Software Data Center 11.3: Upgrade to a release greater than or equal to 11.3.10 See the release notes ([https://www.atlassian.com/software/jira/download-archives]). You can download the latest version of Jira Software Data Center 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 a network application framework for development of protocol servers and clients. Prior to 4.1.136.Final and 4.2.16.Final, Netty SPDY header decoding continues inflating zlib-compressed header blocks after the raw header parser has exceeded `maxHeaderSize` and marked the frame truncated in `SpdyFrameCodec`, allowing a remote peer to send a small compressed `HEADERS` block that expands into much larger raw header data and causes compression-amplified CPU and allocation churn. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.

EPSS 0.42% · 34.9th percentile