🛡️ CVE-2026-21577 — confluence-data-center

🟡 CVSS 6.5 — Medium ✅ No Known Exploit CWE-400 NVD
6.5
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

This High severity DoS (Denial of Service) vulnerability was introduced in versions 9.0.1, 9.1.0, 9.2.0, 9.3.1, 9.4.0, 9.5.1, 10.0.2, 10.1.0 and 10.2.0 of Confluence Data Center.

This DoS (Denial of Service) vulnerability, with a CVSS Score of 7.1, allows an authenticated 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.

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 9.2: Upgrade to a release greater than or equal to 9.2.17

Confluence Data Center 10.2: Upgrade to a release greater than or equal to 10.2.7

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]).

This vulnerability was reported via our Penetration Testing program.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs low-level privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability high.

Weakness class

CVE-2026-21577 is classified as CWE-400: Uncontrolled Resource Consumption. A request can consume memory, CPU or storage without limit, exhausting capacity for everyone else.

Affected software

CVE-2026-21577 is recorded against 1 package.

  • confluence-data-center (from 10.2.0 up to 10.2.6)

Timeline and source

Published on 21 July 2026 and last revised on 10 August 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

confluence.atlassian.com
jira.atlassian.com

Details

Severity MEDIUM
CVSS Score 6.5
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CWE CWE-400
Public Exploit ✅ No
Source NVD
Published 2026-07-21
Updated 2026-08-11
Modified 2026-08-10
Fix URL N/A

Affected Packages

Software From version Fixed in
confluence-data-center 10.2.0 10.2.6

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