This High severity Third-Party Dependency vulnerability was introduced in versions 7.13.0, 7.19, 8.1.0, 8.2.0, 8.3.0 and 8.5 of Confluence Data Center and Server.

This Third-Party Dependency 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 expose assets in your environment susceptible to exploitation which has no impact to confidentiality, no impact to integrity, high impact to availability, and requires no user interaction.

Atlassian recommends that Confluence 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:

• Confluence Data Center and Server 8.6: Upgrade to a release greater than or equal to 8.6.0

See the release notes (https://confluence.atlassian.com/doc/confluence-release-notes-327.html). You can download the latest version of Confluence Data Center and Server from the download center (https://www.atlassian.com/software/confluence/download-archives).

The National Vulnerability Database provides the following description for this vulnerability: Certain Neko-related HTML parsers allow a denial of service via crafted Processing Instruction (PI) input that causes excessive heap memory consumption. In particular, this issue exists in HtmlUnit-Neko through 2.26, and is fixed in 2.27. This issue also exists in CyberNeko HTML through 1.9.22 (also affecting OWASP AntiSamy before 1.6.6), but 1.9.22 is the last version of CyberNeko HTML. NOTE: this may be related to CVE-2022-24839.