CVE-2021-26085 Atlassian Confluence Server Pre-Authorization Arbitrary File Read Vulnerability
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.
From the CISA KEV catalogue version 2026.11.06, with Cybergen analysis. Updated 6 Nov 2026.
Should You Worry?
- CISA confirmed exploitation in the wild and added it to the Known Exploited Vulnerabilities catalogue on 28 Mar 2022.
- CISA lists it as known to be used in ransomware campaigns.
- Rated Medium severity (CVSS 5.3, scored by CISA).
- This product type is often exposed to the internet, which is where attackers scan for it first.
- It has been in the catalogue for 1,684 days. Systems still unpatched now have almost certainly been scanned for it.
What It 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.
Affected Versions
| Product | Versions |
|---|---|
| Atlassian Confluence Server | unspecified to before 7.4.10 7.5.0 to before unspecified unspecified to before 7.12.3 |
| Atlassian Confluence Data Center | unspecified to before 7.4.10 7.5.0 to before unspecified unspecified to before 7.12.3 |
From the public CVE record, as supplied by the vendor. Always confirm against the vendor advisory.
What To Do Now
- 1
Find it
Search your asset inventory and external attack surface for Atlassian Confluence Server. Include cloud images, appliances and anything a supplier runs for you.
Attack Surface Management - 2
- 3
Hunt for compromise
If an affected system was reachable before you patched, assume it may have been hit. Check logs, new accounts, web shells and outbound connections from the date of exposure.
Incident Response - 4
Prove it is fixed
Rescan or test the system after patching. Upgrades that fail silently and forgotten secondary instances are common.
Penetration Testing
Vendor Advisories
The Compliance Clock
General guidance, not legal advice. Your obligations depend on your sector, scope and jurisdiction.
Not Sure If You Are Exposed?
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