CVE-2021-26085
Atlassian Confluence Data Center ≤ 7.4.10
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:NCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2021-26085 is a medium-severity Forced Browsing (CWE-425) vulnerability in Atlassian Confluence Data Center. Its CVSS base score is 5.3 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Proc Filesystem (T1003.007); ranked in the top 0.0% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog; a public proof-of-concept is referenced.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2021-26085 is a pre-authorization arbitrary file read vulnerability affecting the /s/ endpoint in Atlassian Confluence Server. The issue impacts versions before 7.4.10 and versions from 7.5.0 before 7.12.3, and is tracked under CWE-425. It carries a CVSS 3.1 score of 5.3, reflecting network attack vector, low complexity, and no required privileges or user interaction, with limited impact to confidentiality.
Remote attackers without authentication can exploit the flaw to access restricted resources on the server. The vulnerability enables direct requests that bypass authorization checks, allowing viewing of files that should otherwise be protected.
Atlassian has addressed the issue in the fixed releases noted above, with details published in CONFSERVER-67893. The vulnerability also appears in the CISA Known Exploited Vulnerabilities catalog, confirming observed real-world exploitation activity. Public proof-of-concept material has been posted to sites such as Packet Storm.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2021-12906
Vulnerability Data
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.
- CWE(s)
- KEV Date Added
- 28 March 2022
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Forcing a decision on every access request, including direct ones, reduces the exploitability of forced browsing by ensuring no unchecked access paths.
Forces all accesses through the reference monitor, preventing direct or forced requests that bypass checks.
Enforcing access for all logical requests prevents unauthorized direct access to protected resources.
Displaying the notification before further access on public systems prevents direct resource requests from bypassing the required system use terms and consent.
Decoy endpoints catch forced browsing and direct requests, deflecting attackers from legitimate resources while enabling analysis.
Blocks unauthorized direct requests or forced browsing by denying input access to non-authorized actors.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
A.5.15 directly requires defining/implementing access control rules, authorization, need-to-know, and restrictions that enforce appropriate access on all URLs/resources, which stops forced browsing exploitation even if the flaw remains; remainder is bounded to non-authorization cases like path traversal or CSRF (per AC-3 anchor).