How severe is CVE-2026-21579?

CVE-2026-21579 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2026-21579 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (18th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-21579?

CVE-2026-21579 affects Atlassian Confluence Data Center. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-21579?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2026-21579 published?

CVE-2026-21579 was published on 2026-07-21 and last updated on 2026-08-11.

CVE-2026-21579

CVE-2026-21579 is a high-severity vulnerability in Atlassian Confluence Data Center with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-200.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v4: 8.2
EPSS exploit prediction: 0% (18th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-200
Affected product: Atlassian Confluence Data Center
Published: 2026-07-21
Last modified: 2026-08-11

Description

This High severity Information Disclosure vulnerability was introduced in versions 7.17.0, 7.19.0, 8.5.0, 8.9.0, 9.0.1, 9.1.0, 9.2.0, 10.0.2, 10.1.0, and 10.2.0 of Confluence Data Center. This Information Disclosure vulnerability, with a CVSS Score of 8.2, allows an unauthenticated attacker to view sensitive information via an Information Disclosure vulnerability. 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 9.2.22 Confluence Data Center 10.2: Upgrade to a release greater than or equal to 10.2.14 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 Atlassian (Internal) program.

Frequently asked questions

What is CVE-2026-21579?: This High severity Information Disclosure vulnerability was introduced in versions 7.17.0, 7.19.0, 8.5.0, 8.9.0, 9.0.1, 9.1.0, 9.2.0, 10.0.2, 10.1.0, and 10.2.0 of Confluence Data Center. This Information Disclosure vulnerability, with a CVSS Score of 8.2, allows an unauthenticated attacker to view sensitive information via an Information Disclosure vulnerability. 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 9.2.22 Confluence Data Center 10.2: Upgrade to a release greater than or equal to 10.2.14 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 Atlassian (Internal) program.
How severe is CVE-2026-21579?: CVE-2026-21579 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2026-21579 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (18th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-21579?: CVE-2026-21579 affects Atlassian Confluence Data Center. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-21579?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2026-21579 published?: CVE-2026-21579 was published on 2026-07-21 and last updated on 2026-08-11.

References

Affected products (1)

cpe:2.3:a:atlassian:confluence_data_center:*:*:*:*:*:*:*:*

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