Outline's Local File Storage Feature can Cause CSP Bypass
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- Cross-site scripting
- Confidentiality · integrity · availability
- High · None · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-79.
Summary
Outline is a service that allows for collaborative documentation. In versions 0.72.0 through 0.83.0, Outline introduced a feature which facilitates local file system storage capabilities as an optional file storage strategy. This feature allowed a CSP bypass as well as a ContentType bypass that might facilitate further attacks. In the case of self-hosting and using Outline FILE_STORAGE=local on the same domain as the Outline application, a malicious payload can be uploaded as a file attachment and bypass those CSP restrictions, allowing script execution within the context of another user. This is fixed in version 0.84.0.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA outline (outline) Fixed in 0.84.0
Timeline
- 2026-10-02 Threatist record created from CVE-2025-58351
References
More Outline vulnerabilities
- TI-2026-26021 Outline has a rate limit bypass that allows brute force of email login OTP CVSS 4.0CRITICAL 9.1
- TI-2026-20086 Outline's IDOR allows unauthorized viewing and seizing of private deleted drafts CVSS 3.1HIGH 8.8
- TI-2024-25167 An issue in Outline <= v0.76.1 allows attackers to execute a session hijacking attack via… CVSS 3.1HIGH 8.8
- TI-2026-30168 Outline has IDOR in document share creation that allows unauthorized access to private documents across workspaces CVSS 3.1HIGH 7.7
- TI-2024-27038 Stored Cross-site Scripting (XSS) vulnerability in Outline editor CVSS 3.1HIGH 7.3
- TI-2026-32586 Outline: Slack OAuth state can link a victim Outline account to an attacker Slack identity CVSS 3.1MEDIUM 6.5
Sources
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences