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.
- Vendor
- Atlassian
- Product
- Confluence Server
- CVSS
- 5.3
- EPSS (exploit probability)
- 99.9%
- Status
- kevransomware use
- CISA patch-by (BOD 22-01)
- Added to KEV
Is CVE-2021-26085 being exploited?
Yes. CISA added CVE-2021-26085 to its Known Exploited Vulnerabilities catalog on . CISA only lists a CVE when it has reliable evidence of exploitation in the wild. CISA marks it as known to be used in ransomware campaigns.
FIRST's EPSS model puts the probability of exploitation activity in the next 30 days at 99.9% (scored October 14, 2026).
- CISA KEV[ LISTED ]
- ENISA EUVD (exploited)[ — ]
- CIRCL KEV[ — ]
Catalog snapshot 2026-11-13. Full cross-catalog view: /kev-comparison
CVE-2021-26085 timeline
Every event links to its source. Catalog dates are each catalog's own; day offsets count from NVD publication. Data: JSON
What to do
CISA required actionApply updates per vendor instructions.
US federal civilian agencies must remediate by (21 days after listing) under BOD 22-01. Everyone else: that deadline is a sensible upper bound, not a target. Vendor guidance and the NVD record are linked under Source above.
Other Atlassian Confluence Server and Data Center CVEs we track
| CVE / Vulnerability | Severity | CVSS | EPSS | Added to KEV |
|---|---|---|---|---|
| CVE-2023-22527 Atlassian Confluence Data Center and Server Template Injection Vulnerabilityransomware use | [ CRITICAL ] | 9.8 | 100.0% | |
| CVE-2023-22518 Atlassian Confluence Data Center and Server Improper Authorization Vulnerabilityransomware use | [ CRITICAL ] | 9.8 | 100.0% | |
| CVE-2023-22515 Atlassian Confluence Data Center and Server Broken Access Controlransomware usewrite-up | [ CRITICAL ] | 9.8 | 99.2% | |
| CVE-2022-26138 Atlassian Questions For Confluence App Hard-coded Credentials Vulnerability | [ CRITICAL ] | 9.8 | 98.2% | |
| CVE-2022-26134 Atlassian Confluence OGNL Injection Remote Code Executionransomware usewrite-up | [ CRITICAL ] | 9.8 | 100.0% | |
| CVE-2021-26084 Atlassian Confluence Server and Data Center Object-Graph Navigation Language (OGNL) Injection Vulnerabilityransomware use | [ CRITICAL ] | 9.8 | 100.0% | |
| CVE-2019-3398 Atlassian Confluence Server and Data Center Path Traversal Vulnerability | [ HIGH ] | 8.8 | 97.0% | |
| CVE-2019-3396 Atlassian Confluence Server and Data Center Server-Side Template Injection Vulnerabilityransomware use | [ CRITICAL ] | 9.8 | 99.9% |