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Vulnerabilities

Vulnerability · CVE-2026-21577

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.

Published Jul 21, 2026 · catalog updated Oct 24, 2026 · confluence data center

Open the advisory

Exploitation likelihood is not on this record for CVE-2026-21577. A missing EPSS score is not a low risk. Compare confluence data center with the linked advisory before you change production.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
  • EPSS is missing. A missing score is not a low risk.
Severity
High7.1
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
Not in the current FIRST EPSS dataset
Remediation
Version ranges on file
Affected products
cpe atlassian/confluence data center

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe atlassian/confluence data center>= 10.0.2, <= 10.0.3
  • cpe atlassian/confluence data center>= 10.1.0, <= 10.1.2
  • cpe atlassian/confluence data center>= 9.0.1, <= 9.0.3
  • cpe atlassian/confluence data center>= 9.1.0, <= 9.1.1
  • cpe atlassian/confluence data center>= 9.2.0, <= 9.2.15
  • cpe atlassian/confluence data center>= 9.3.1, <= 9.3.2
  • cpe atlassian/confluence data center>= 9.4.0, <= 9.4.1
  • cpe atlassian/confluence data center>= 9.5.1, <= 9.5.4

How to fix CVE-2026-21577

  • Recommended remediation

    Affected version ranges suggest a fixed boundary. Verify against the vendor advisory for your release.

  • Official advisories

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

Exploitation likelihood is not on this record for CVE-2026-21577. A missing EPSS score is not a low risk. Compare confluence data center with the linked advisory before you change production.

Which versions are affected?

Compare what you have installed with atlassian/confluence data center >= 10.0.2, <= 10.0.3; atlassian/confluence data center >= 10.1.0, <= 10.1.2; atlassian/confluence data center >= 9.0.1, <= 9.0.3; atlassian/confluence data center >= 9.1.0, <= 9.1.1. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-400: Uncontrolled Resource Consumption. EPSS is absent from the current FIRST dataset. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Jul 21, 2026 · NIST NVD

    Detected

    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 h

  2. Oct 24, 2026 · NIST NVD

    Updated

    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 h

Sources

  • NIST NVDVulnerability recordCVE-2026-21577

    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 atta

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 24, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.