CVE-2021-26085: Atlassian Confluence Server Pre-Authorization Arbitrary File Read Vulnerability
- Is it exploited?
Yes. CISA added it to the Known Exploited Vulnerabilities catalog on , 237 days after the CVE record was published.
- How likely is exploitation in the next 30 days?
- 99.9%
EPSS score, percentile 100 of all scored records
- How severe?
- 5.3 Medium
CVSS v3.1 base score, from CISA's enrichment of the record
- What should I do?
CISA deadline . Apply updates per vendor instructions.
The CVE record links no vendor advisory, patch or mitigation.
- Which versions are affected?
Affected
- before 7.4.10
- 7.5.0
- before 7.12.3
- before 7.4.10
- 7.5.0
- before 7.12.3
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
What to do
Required action, set by CISA
Apply updates per vendor instructions.
CISA due date for this action: .
Advisories and patches
The CVE record links no vendor advisory, patch or mitigation.
Linked from CISA's catalog entry
Affected products and versions
As listed in the CVE record.
| Status | Versions |
|---|---|
| Affected | before 7.4.10 |
| Affected | 7.5.0 |
| Affected | before 7.12.3 |
| Status | Versions |
|---|---|
| Affected | before 7.4.10 |
| Affected | 7.5.0 |
| Affected | before 7.12.3 |
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
About this 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.
Summary: CISA's KEV catalog, as of .
- CISA added CVE-2021-26085 to its Known Exploited Vulnerabilities (KEV) catalog on 28 Mar 2022.
- CISA marks it as known to be used in ransomware campaigns.
- The due date CISA sets for the required action is 18 Apr 2022.
- The CVE record was published on 3 Aug 2021, 237 days before it was added to KEV.
- The CVE record carries a CVSS v3.1 base score of 5.3 (Medium), taken from CISA's enrichment of the record.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 99.9% (percentile 100), as of 28 Oct 2026.
- CISA's SSVC assessment in the CVE record: exploitation active, automatable yes, technical impact partial.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of . About the data.
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. The affected versions are before version 7.4.10, and from version 7.5.0 before 7.12.3.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
Weakness
- CWE-425: Direct Request ('Forced Browsing')
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.
Timeline
| Date | Event |
|---|---|
| CVE record published | |
| Added to CISA KEV | |
| CISA due date for the required action | |
| CVE record last updated |
References
More exploited Atlassian vulnerabilities
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- CVE-2021-26086: Atlassian Jira Server and Data Center Path Traversal Vulnerability
- CVE-2023-22527: Atlassian Confluence Data Center and Server Template Injection Vulnerability
- CVE-2023-22518: Atlassian Confluence Data Center and Server Improper Authorization Vulnerability
- CVE-2023-22515: Atlassian Confluence Data Center and Server Broken Access Control Vulnerability
- CVE-2022-36804: Atlassian Bitbucket Server and Data Center Command Injection Vulnerability