CVE-2024-40626Public exploitNetwork attack vector

Stored XSS via unchecked mention label type

Published Jul 16, 2024 · Updated Aug 2, 2024

Stored XSS in Outline before 0.77.3 allows remote authenticated users to execute JavaScript when another user views a crafted comment. The mention node's toDOM method passes node.attrs.label directly into ProseMirror's DOMOutputSpec, so an attacker-supplied array becomes a script element instead of text. Exploitation requires an authenticated account and a victim to view the stored content; loading an attached payload also requires self-hosted file storage on the Outline origin.

CVSS severity7.3
High
EPSS probability0.52%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Outline before 0.77.3 allows remote authenticated users to execute JavaScript when another user views a crafted comment. The mention node's toDOM method passes node.attrs.label directly into ProseMirror's DOMOutputSpec, so an attacker-supplied array becomes a script element instead of text. Exploitation requires an authenticated account and a victim to view the stored content; loading an attached payload also requires self-hosted file storage on the Outline origin.

The record

CVE
CVE-2024-40626
Published
Jul 16, 2024
Updated
Aug 2, 2024
Vendor
Outline
Product
Outline
Classifications
CWE-843, CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 16, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <0.77.3
  2. Affected versionversion=< 0.77.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Outline · Outlineversion=0 <0.77.3; version=< 0.77.3

Published CVSS scores

5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
7.3GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-843Access of Resource Using Incompatible Type ('Type Confusion')
CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007JavaScript/JScript

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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