What is CVE-2026-43889?

CVE-2026-43889 is a medium-severity vulnerability in Outline, classified under Incorrect Authorization. CVSS score: 6.5/10. Published 2026-05-11.

How severe is CVE-2026-43889?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Auth bypass in Outline

CVE-2026-43889

Outline is a service that allows for collaborative documentation. Prior to 1.7.0, the shares.create API accepts both collectionId and documentId simultaneously and, when published=false, only verifies read access for each—skipping the "sha…

Vulnerability class: Broken Access Control

EPSS: 0.000 (14.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N.

Affected products

Outline — versions < 1.7.0

Weakness classification (CWE)

CWE-863 — Incorrect Authorization

References

security-advisories@github.com (x_refsource_CONFIRM)

Frequently asked questions

What is CVE-2026-43889?: CVE-2026-43889 is a medium-severity vulnerability in Outline, classified under Incorrect Authorization. CVSS score: 6.5/10. Published 2026-05-11.
How severe is CVE-2026-43889?: Medium severity. CVSS v3 base score is 6.5 out of 10.