CVE-2021-26085
MediumExploitedPublic exploitAffected versions of Atlassian Confluence Server allow remote attackers to view restricted resources via a Pre-Authorization Arbitrary File Read vulnerability in the /s/ endpoint.
Published Aug 2, 2021 · Updated Oct 24, 2025
Key Facts
Patch immediately- CVE-2021-26085 is a medium-severity vulnerability (CVSS 5.3 v3.1) affecting Confluence Data Center (Atlassian), Confluence Server (Atlassian).
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Mar 28, 2022 and is known to be used in ransomware campaigns. Public exploit code is available.
- EPSS estimates a 100% probability of exploitation in the next 30 days.
- Fixed versions are available, including Confluence Data Center 7.4.10, Confluence Data Center 7.12.3, Confluence Data Center unspecified.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
5.3
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
EPSS (30-day exploit likelihood)
100%
Higher than 99.9% of all scored CVEs
Exploited in the wild
Yes
4 catalog listings, used by ransomware
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2021-26085 brief as a PDF
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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.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | Mar 28, 2022 | Apr 18, 2022 | Known |
| Industry KEV feed | Mar 28, 2022 | Apr 18, 2022 | Known |
| CIRCL KEV | Mar 28, 2022 | Apr 18, 2022 | Known |
| ENISA EUVD | Mar 28, 2022 | n/a | Not reported |
Required action: Apply updates per vendor instructions.
Affected Products
4 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Confluence Data CenterAtlassian | >= unspecified | 7.4.10 |
| Confluence ServerAtlassian | >= unspecified | 7.4.10 |
Patched Releases
Confluence Data Center
7.4.10, 7.12.3, unspecified
Confluence Server
7.4.10, 7.12.3, unspecified
Timeline
Publicly disclosed
Aug 2, 2021
Added to CISA KEV
Mar 28, 2022
Added to Industry KEV feed
Mar 28, 2022
Added to CIRCL KEV
Mar 28, 2022
Added to ENISA EUVD
Mar 28, 2022
Last updated
Oct 24, 2025
Weakness Type
- CWE-425 Direct Request ('Forced Browsing')
References
- advisoryhttps://jira.atlassian.com/browse/CONFSERVER-67893
- exploithttp://packetstormsecurity.com/files/164401/Atlassian-Confluence-Server-7.5.1-Arbitrary-File-Read.html
- exploitVulnCheck exploitation report
- exploitVulnCheck exploitation report
- exploitVulnCheck exploitation report
FAQ
Common Questions.
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: Confluence Data Center (Atlassian) versions >= unspecified; Confluence Server (Atlassian) versions >= unspecified. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Mar 28, 2022 and is known to be used in ransomware campaigns.
Yes. It was added on Mar 28, 2022 with a federal remediation due date of Apr 18, 2022.
Public exploit code is available.
Fixed versions are available, including Confluence Data Center 7.4.10, Confluence Data Center 7.12.3, Confluence Data Center unspecified.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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