CVE-2026-21577

Summary

CVE	CVE-2026-21577
State	PUBLISHED
Assigner	atlassian
Source Priority	CVE Program / NVD first with legacy fallback
Published	2026-07-21 18:16:57 UTC
Updated	2026-07-22 19:16:59 UTC
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.

Risk And Classification

Primary CVSS: v4.0 7.1 HIGH from [email protected]

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS: 0.002350000 probability, percentile 0.144520000 (date 2026-07-22)

Problem Types: CWE-400 | DoS (Denial of Service) | CWE-400 CWE-400 Uncontrolled Resource Consumption

Version	Source	Type	Score	Severity	Vector
4.0	[email protected]	Secondary	7.1	HIGH	`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/C...`
4.0	CNA	DECLARED	7.1	HIGH	`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`

CVSS v4.0 Breakdown

Attack Vector

Network

Attack Complexity

Low

Attack Requirements

None

Privileges Required

Low

User Interaction

None

Confidentiality

None

Integrity

None

Availability

High

Sub Conf.

None

Sub Integrity

None

Sub Availability

None

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Vendor Declared Affected Products

Source	Vendor	Product	Version	Platforms
CNA	Atlassian	Confluence Data Center	affected 10.2.0 to 10.2.6	Not specified
CNA	Atlassian	Confluence Data Center	affected 10.1.0 to 10.1.2	Not specified
CNA	Atlassian	Confluence Data Center	affected 10.0.2 to 10.0.3	Not specified
CNA	Atlassian	Confluence Data Center	affected 9.5.1 to 9.5.4	Not specified
CNA	Atlassian	Confluence Data Center	affected 9.4.0 to 9.4.1	Not specified
CNA	Atlassian	Confluence Data Center	affected 9.3.1 to 9.3.2	Not specified
CNA	Atlassian	Confluence Data Center	affected 9.2.0 to 9.2.15	Not specified
CNA	Atlassian	Confluence Data Center	affected 9.1.0 to 9.1.1	Not specified
CNA	Atlassian	Confluence Data Center	affected 9.0.1 to 9.0.3	Not specified
CNA	Atlassian	Confluence Data Center	unaffected 10.2.7 to 10.2.14	Not specified
CNA	Atlassian	Confluence Data Center	unaffected 9.2.17 to 9.2.22	Not specified

References

Reference	Source	Link	Tags
confluence.atlassian.com/pages/viewpage.action	[email protected]	confluence.atlassian.com
jira.atlassian.com/browse/CONFSERVER-104334	[email protected]	jira.atlassian.com
CVE Program record	CVE.ORG	www.cve.org	canonical
NVD vulnerability detail	NVD	nvd.nist.gov	canonical, analysis

No vendor comments have been submitted for this CVE.

There are currently no legacy QID mappings associated with this CVE.