Exploited. On CISA's list since 2022-03-28, and used by ransomware.
Atlassian Confluence Server Pre-Authorization Arbitrary File Read Vulnerability
CVE-2021-26085 · Atlassian Confluence Server · Published 2021-08-03
How bad would it be?
5.3 out of 10
CVSS rates it medium.
How likely is it to be used?
over 99%
Estimated chance of exploitation in the next 30 days, among the top 1% of all scored flaws (EPSS, 2026-10-29).
Is it already being used?
Yes
CISA has seen it exploited in real attacks. For US government agencies the fix is deadline passed 1656 days ago (2022-04-18).
What CISA says to do
Apply updates per vendor instructions.
Affected versions of Atlassian Confluence Server allow remote attackers to view restricted resources via a pre-authorization arbitrary file read vulnerability in the /s/ endpoint.
What the flaw is
Affected versions of Atlassian Confluence Server allow remote attackers to view restricted resources via a Pre-Authorization Arbitrary File Read vulnerability in the /s/ endpoint. The affected versions are before version 7.4.10, and from version 7.5.0 before 7.12.3.
From the NVD.
Fixes and advisories
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Understand the kind of weakness behind this flaw. These resources teach the weakness, rather than reproduce this specific CVE. Follow the vendor's advice above to fix the affected product.
CWE-425 · CISA KEV; NVD record: 134c704f-9b21-4f2e-91b3-4a467353bcc0; NVD record: nvd@nist.gov. We have not selected a close learning match for this label.
CWE is a catalogue of weakness types. Labels come from the sources shown and can differ or change. Resource matches reviewed 16 October 2026.
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Exploited flaws from CISA's KEV catalogue. Chance of exploitation from EPSS by FIRST. Descriptions and scores from the NVD. This product uses the NVD API but is not endorsed or certified by the NVD.