What is CVE-2026-63097?

CVE-2026-63097 is a medium-severity vulnerability in Matrix-org Dendrite, classified under Incorrect Authorization. CVSS score: 4.3/10. Published 2026-07-17.

How severe is CVE-2026-63097?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Auth bypass in Matrix-org Dendrite

CVE-2026-63097

Dendrite through 0.13.8 contains an improper access control vulnerability in the syncapi /context endpoint (syncapi/routing/context.go) that allows authenticated local users to access post-leave room state events by exploiting a flawed mem…

Vulnerability class: Broken Access Control

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.

Affected products

Matrix-org Dendrite — versions 0

Weakness classification (CWE)

CWE-863 — Incorrect Authorization

References

disclosure@vulncheck.com (technical-description, exploit)
disclosure@vulncheck.com (third-party-advisory)

Frequently asked questions

What is CVE-2026-63097?: CVE-2026-63097 is a medium-severity vulnerability in Matrix-org Dendrite, classified under Incorrect Authorization. CVSS score: 4.3/10. Published 2026-07-17.
How severe is CVE-2026-63097?: Medium severity. CVSS v3 base score is 4.3 out of 10.