Raw vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/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-2026-24901 is a high-severity Authorization Bypass Through User-Controlled Key (CWE-639) vulnerability in Getoutline Outline. Its CVSS base score is 8.1 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 23th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified map to AC-24 (Access Control Decisions) and AC-3 (Access Enforcement) — see the control section below for these in your framework.
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-2026-24901 is an Insecure Direct Object Reference (IDOR) vulnerability, classified under CWE-639, affecting the Outline collaborative documentation service in versions prior to 1.4.0. The flaw resides in the document restoration logic, where ownership validation is bypassed, enabling unauthorized access to deleted drafts. Outline, published on March 17, 2026, carries a CVSS v3.1 base score of 8.1 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N), indicating high confidentiality and integrity impacts with low complexity and privileges required.
Any authenticated team member can exploit this vulnerability remotely without user interaction. By targeting the restore process, attackers can unauthorizedly restore, view, and seize ownership of deleted drafts belonging to other users, including administrators. This grants access to sensitive private information and effectively locks the original owner out of their content.
The GitHub security advisory (GHSA-gmr5-43f5-79f5) confirms that upgrading to Outline version 1.4.0 resolves the issue by addressing the ownership validation bypass in the restoration logic. Security practitioners should prioritize patching affected instances to prevent unauthorized data access and ownership hijacking.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-12582
Vulnerability Data
Outline is a service that allows for collaborative documentation. Prior to 1.4.0, an Insecure Direct Object Reference (IDOR) vulnerability in the document restoration logic allows any team member to unauthorizedly restore, view, and seize ownership of deleted drafts belonging to…
more
other users, including administrators. By bypassing ownership validation during the restore process, an attacker can access sensitive private information and effectively lock the original owner out of their own content. Version 1.4.0 fixes the issue.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Enforcing approved authorizations on every access request structurally stops a user-controlled key from reaching another user's data.
Requiring explicit access-control decisions on each request blocks unauthorized key-driven access.
Least-privilege restrictions limit the scope of data reachable even if a key check is bypassed.
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.
Enforcing authorization policy and least privilege directly blocks user-controlled key tampering that bypasses access checks.
Logical access controls prevent unauthorized data access that results from missing authorization checks on object references.
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.
Security testing can detect missing authorization checks but does not prevent the weakness in production.
Information access restriction explicitly enforces that users may only retrieve data they are authorized to see, directly addressing user-controlled key bypass.
Access control policy directly requires enforcement of authorization rules that prevent unauthorized access via manipulated keys.
Managing access rights includes ensuring users can only access their own records and not bypass authorization by altering identifiers.
Privileged access rights control restricts what data each user may access, mitigating direct object reference attacks.
Secure development lifecycle includes authorization design but does not itself implement runtime access checks.