Atlassian Confluence Data Center denial of service

CVSS Meta Temp Score
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CTI Interest Score
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4.3$0-$5k0.57

Summaryinfo

A vulnerability labeled as problematic has been found in Atlassian Confluence Data Center. The impacted element is an unknown function. Executing a manipulation can lead to denial of service. This vulnerability is tracked as CVE-2026-21577. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability has been found in Atlassian Confluence Data Center (the affected version unknown) and classified as problematic. This vulnerability affects an unknown part. The manipulation with an unknown input leads to a denial of service vulnerability. The CWE definition for the vulnerability is CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. As an impact it is known to affect availability. CVE summarizes:

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.

The advisory is shared for download at confluence.atlassian.com. This vulnerability was named CVE-2026-21577 since 01/01/2026. The exploitation appears to be easy. The attack can be initiated remotely. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1499.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Vendor

Name

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.3
VulDB Meta Temp Score: 4.3

VulDB Base Score: 4.3
VulDB Temp Score: 4.3
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Denial of service
CWE: CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

01/01/2026 CVE reserved
07/21/2026 +200 days Advisory disclosed
07/21/2026 +0 days VulDB entry created
07/21/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: atlassian.com

Advisory: confluence.atlassian.com
Status: Confirmed

CVE: CVE-2026-21577 (🔒)
GCVE (CVE): GCVE-0-2026-21577
GCVE (VulDB): GCVE-100-380992

Entryinfo

Created: 07/21/2026 19:55
Changes: 07/21/2026 19:55 (50)
Complete: 🔍
Cache ID: 216::103

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