CVE-2021-26085 kev+ ransomware in the critical feed json
Affected versions of Atlassian Confluence Server allow remote attackers to view restricted resources via a Pre-Authorization Arbitrary File…
published 2021-08-03 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-12906
- cvss
- 5.3
- version 3.1, CNA
- cisa kev
- Exploited
- added 2022-03-28, used in ransomware
- epss
- 99.9%
- EPSS 99.9% chance of exploitation in 30 days, percentile 99.9%
- public exploits
- 1
- Exploit-DB, plus a Nuclei check
Summary
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.
Patch / fix
cisa required action Apply updates per vendor instructions.
- Atlassian Confluence Server 7.4.10, 7.12.3
- Atlassian Confluence Data Center 7.4.10, 7.12.3
Timeline
- Published
- First public exploit (EDB-50377)
- Added to CISA KEV
- CISA patch deadline
- CISA SSVC: exploitation active
Known exploited
- Added
- 4 y ago
- Patch by
- 2022-04-18 (4 y ago)
- Ransomware
- Known to be used in ransomware campaigns
- Required action
- Apply updates per vendor instructions.
- Vendor, product
- Atlassian, Confluence Server
- CISA name
- Atlassian Confluence Server Pre-Authorization Arbitrary File Read Vulnerability
ATT&CK techniques
How it is exploited and what it leads to, in MITRE ATT&CK terms.
kev release 2025-07-28, att&ck v16.1. KEV to ATT&CK mappings by the MITRE Center for Threat-Informed Defense (Mappings Explorer, Apache-2.0). © 2026 The MITRE Corporation. This work is reproduced and distributed with the permission of The MITRE Corporation. Terms of use
CISA SSVC
- Exploitation
- Active, exploited in the wild
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 21 mo ago
Exploit prediction
99.94% chance of exploitation in the next 30 days, higher than 99.9% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- EDB-50377 Atlassian Confluence 7.12.2 - Pre-Authorization Arbitrary File Read webapps, 2021-10-05
- Nuclei template Atlassian Confluence Server - Local File Inclusion nuclei detection template
- packetstormsecurity.com http://packetstormsecurity.com/files/164401/Atlassian-Confluence-Server-7.5.1-Arbitrary-File-Read.html referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CISA ADP | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N |
| NVD | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N |
| CNA | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N |
| NVD | 2.0 | 5.0 | AV:N/AC:L/Au:N/C:P/I:N/A:N |
Affected products
- Atlassian Confluence Server
- Atlassian Confluence Data Center
Classification
- Weakness
-
- CWE-425 Direct Request
References
-
packetstormsecurity.com
/files/164401/Atlassian-Confluence-Server-7.5.1-Arbitrary-File-Read.html
exploit, third-party-advisory, vdb-entry
-
jira.atlassian.com
/browse/CONFSERVER-67893
issue-tracking, vendor-advisory
-
cisa.gov
/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26085
government-resource, us-government-resource
Sources
- CVE List CVE-2021-26085
- NVD CVE-2021-26085
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.