CVE-2021-26085: Atlassian Confluence Server Pre-Authorization Arbitrary File Read Vulnerability

Reference page built from the source records below, each shown as its source publishes it. Dataset version ref-e61d45eac0b3, updated 2026-11-02T23:39:54.475Z.

CISA Known Exploited Vulnerabilities

Name: Atlassian Confluence Server Pre-Authorization Arbitrary File Read Vulnerability
Vendor: Atlassian
Product: Confluence Server
Added to the catalog: 2022-03-28
Due date for US federal agencies: 2022-04-18
Weaknesses: CWE-425
Catalog version: 2026.10.30

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.

Required action (CISA)

Apply updates per vendor instructions.

Ransomware use: CISA marks this vulnerability as known to be used in ransomware campaigns. CISA does not say which group used it.

Links in CISA's notes

https://nvd.nist.gov/vuln/detail/CVE-2021-26085

Read on 2026-11-02T23:39:54.475Z under licence cisa-kev-cc0@b0067899 from https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json

NVD analysis

Status: Analyzed
Published: 2021-08-03T00:15:08.557
Last modified: 2026-06-17T03:42:49.933
Weaknesses: CWE-425

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.

Metric	Score	Severity	Vector	Scored by
CVSS 3.1	5.3	MEDIUM	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N	[email protected] (Primary)
CVSS 3.1	5.3	MEDIUM	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N	134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary)
CVSS 2.0	5	MEDIUM	AV:N/AC:L/Au:N/C:P/I:N/A:N	[email protected] (Primary)

References

http://packetstormsecurity.com/files/164401/Atlassian-Confluence-Server-7.5.1-Arbitrary-File-Read.html (Exploit, Third Party Advisory, VDB Entry)
https://jira.atlassian.com/browse/CONFSERVER-67893 (Issue Tracking, Vendor Advisory)
http://packetstormsecurity.com/files/164401/Atlassian-Confluence-Server-7.5.1-Arbitrary-File-Read.html (Exploit, Third Party Advisory, VDB Entry)
https://jira.atlassian.com/browse/CONFSERVER-67893 (Issue Tracking, Vendor Advisory)
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26085 (US Government Resource)

This product uses the NVD API but is not endorsed or certified by the NVD.

Read on 2026-11-02T23:41:59.479Z under licence nvd-api-terms-of-use@ff2a5288 from https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2021-26085

CVE record

Assigner: atlassian
State: PUBLISHED
Published: 2021-08-03T00:00:12.199Z
Updated: 2025-10-21T23:25:39.229Z
Problem types: Pre-Authorization Arbitrary File Read

References

https://jira.atlassian.com/browse/CONFSERVER-67893
http://packetstormsecurity.com/files/164401/Atlassian-Confluence-Server-7.5.1-Arbitrary-File-Read.html

Read on 2026-11-03T01:06:47.452Z under licence cve-terms-of-use@81bfa2f3 from https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2021/26xxx/CVE-2021-26085.json

Defensive techniques (MITRE D3FEND)

D3FEND maps these defensive techniques to the weakness (CWE) that NVD lists for this CVE, through the digital artifacts the weakness affects. D3FEND does not say they stop this vulnerability.

CWE-425: Direct Request ('Forced Browsing')

Restore: Restore Software (acts on Software)
Harden: Variable Initialization (acts on Subroutine)
Isolate: Application-based Process Isolation (acts on Subroutine)
Harden: Credential Scrubbing (acts on Subroutine)
Model: Asset Vulnerability Enumeration (acts on Software)
Harden: Trusted Library (acts on Subroutine)
Model: Software Inventory (acts on Software)
Harden: Software Update (acts on Software)
Harden: Domain Logic Validation (acts on Subroutine)

D3FEND ontology version 1.6.0.

Read on 2026-11-02T23:56:32.406Z under licence d3fend-terms-of-use@f98cbc7e from https://d3fend.mitre.org/api/weakness/cwe/CWE-425.json

MITRE D3FEND™ knowledge graph. © 2025 The MITRE Corporation.
"The MITRE Corporation (MITRE) hereby grants you a non-exclusive, royalty-free license to use D3FEND for research, development, and commercial purposes. Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." Terms: https://d3fend.mitre.org/tou/

Sources and licences

CISA
Source: CISA Catalog of Known Exploited Vulnerabilities, version 2026.10.30, CC0 1.0. Use of this data does not imply endorsement by CISA or DHS.
CC0 1.0 Universal
National Vulnerability Database (NIST)
This product uses the NVD API but is not endorsed or certified by the NVD.
NVD API Terms of Use (NIST publications in the public domain, 17 U.S.C. 105)
CVE Program, The MITRE Corporation
Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation. CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy.
CVE Program Terms of Use ("CVE Usage" licence)
MITRE D3FEND
MITRE D3FEND™ knowledge graph. © 2025 The MITRE Corporation.
"The MITRE Corporation (MITRE) hereby grants you a non-exclusive, royalty-free license to use D3FEND for research, development, and commercial purposes. Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." Terms: https://d3fend.mitre.org/tou/
MITRE D3FEND Terms of Use (site + knowledge graph); source repo MIT

Cite this page

Dragons Eye Ransomware Tracker, "CVE-2021-26085: Atlassian Confluence Server Pre-Authorization Arbitrary File Read Vulnerability",
entity page, dataset version ref-e61d45eac0b3, updated 2026-11-02T23:39:54.475Z,
https://ransomware-tracker.com/cve/CVE-2021-26085 (accessed 2026-11-03).
Underlying source: CISA Catalog of Known Exploited Vulnerabilities, version 2026.10.30.
Underlying source: National Vulnerability Database (NIST), CVE API 2.0, record last modified 2026-06-17T03:42:49.933.
Underlying source: CVE List (CVE Program, The MITRE Corporation), record updated 2025-10-21T23:25:39.229Z.
Underlying source: MITRE D3FEND, ontology version 1.6.0.

Pages change. The dataset version identifies the data, but no archive of old versions is kept, so this citation cannot be replayed later.

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