Outline: Slack OAuth state can link a victim Outline account to an attacker Slack identity

Summary

CVECVE-2026-44695
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-05-11 22:22:14 UTC
Updated2026-05-12 14:17:08 UTC
DescriptionOutline is a service that allows for collaborative documentation. Prior to 1.7.1, the Slack integration callback for GET /auth/slack.post accepts an unsigned, session-independent OAuth state value. A third party who can obtain a Slack OAuth code for the same Outline Slack client can make a logged-in Outline user complete the callback and link that user's Outline account to the attacker's Slack team_id and user_id. The linked Slack identity can then use the Slack /outline search command as the victim Outline user. This vulnerability is fixed in 1.7.1.

Risk And Classification

Primary CVSS: v3.1 5.8 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:N/A:N

EPSS: 0.000150000 probability, percentile 0.033880000 (date 2026-05-12)

Problem Types: CWE-352 | CWE-352 CWE-352: Cross-Site Request Forgery (CSRF)


VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary5.8MEDIUMCVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:N/A:N
3.1CNADECLARED5.8MEDIUMCVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:N/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
Low
User Interaction
Required
Scope
Changed
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:N/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Outline Outline affected < 1.7.1 Not specified

References

ReferenceSourceLinkTags
github.com/outline/outline/security/advisories/GHSA-mjgw-5j7q-gv8v 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis
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