CVE-2026-24901

HighPublic PoC

Published: 17 March 2026

Published

17 March 2026

Modified

19 March 2026

KEV Added

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Patch

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CVSS Score 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

EPSS Score 0.0004 12.6th percentile

Risk Priority 16 60% EPSS · 20% KEV · 20% CVSS

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 12.6th 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 are NIST 800-53 AC-3 (Access Enforcement) and SI-10 (Information Input Validation).

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploit Public-Facing Application (T1190) and 3 other techniques. What defenders deploy: see the NIST 800-53 controls recommended below.

Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

AC-3 Access Enforcement good match

prevent

AC-3 mandates enforcement of approved authorizations, directly preventing the IDOR by requiring ownership validation in the document restoration logic.

SI-10 Information Input Validation good match

prevent

SI-10 requires validation of inputs such as document IDs during restoration to ensure only authorized team members can access and restore others' deleted drafts.

SI-2 Flaw Remediation good match

prevent

SI-2 ensures identification and timely remediation of flaws like the ownership bypass, such as patching to Outline version 1.4.0.

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

attack.mitre.org →

T1068 Exploitation for Privilege Escalation Privilege Escalation

Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.

attack.mitre.org →

T1213 Data from Information Repositories Collection

Adversaries may leverage information repositories to mine valuable information.

attack.mitre.org →

T1565.001 Stored Data Manipulation Impact

Adversaries may insert, delete, or manipulate data at rest in order to influence external outcomes or hide activity, thus threatening the integrity of the data.

attack.mitre.org →

Why these techniques?

IDOR in Outline web app (public-facing service) directly enables remote exploitation for unauthorized access to/manipulation of data in documentation repository plus effective privilege escalation via ownership bypass.

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1

NVD Description

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…

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.

Deeper analysisAI

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.