CVE-2021-26085
KEVRansomware UseAtlassian Confluence Server Pre-Authorization Arbitrary File Read Vulnerability
Description
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.
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.
CVSS 3.1 vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:NPublishedAug 3, 2021
Last modifiedJun 17, 2026
Added to KEVMar 28, 2022
Remediation dueApr 18, 2022
References
- packetstormsecurity.com/files/164401/Atlassian-Confluence-Server-7.5.1-Arbitrary-File-Read.htmlExploitThird Party Advisory
- jira.atlassian.com/browse/CONFSERVER-67893Issue TrackingVendor Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26085US Government Resource
0 recent articles mention this CVE
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Risk assessment · High
Actively exploited and used by ransomware crews. Patch immediately.
- Exploitation
- Confirmed in the wild (CISA KEV)
- Federal remediation deadline
- Overdue by 1653 days
- Ransomware
- Used in known ransomware campaigns
- CVSS
- 5.3 MEDIUM
- EPSS (30-day exploit probability)
- 99.9% · top 1% of all CVEs
- Weakness
- CWE-425
- Attack vector
- Network, remotely reachable
- Preconditions
- No privileges and no user interaction
Recommended actions
- 1.Apply updates per vendor instructions.
- 2.Treat as emergency change: patch or isolate internet-facing instances first.
- 3.Review exposure: confirm which instances are reachable from the internet and restrict access until patched.
- 4.Hunt for compromise: review logs for the disclosure window, not just from the patch date.
- 5.Verify offline/immutable backups and segment the affected systems. This flaw is used for ransomware initial access.
Assessment is derived automatically from the live signals above; verify against your own asset inventory.