CVE-2026-63095 Dendrite 0.13.8 Improper Authorization via POST account/3pid/delete Endpoint
Authenticated users can delete other users' third-party identifier bindings, enabling account takeover via password reset hijacking.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-63095?
CVE-2026-63095 is a high-severity missing authorization vulnerability in matrix-org dendrite, published on 17 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Dendrite through 0.13.8 contains an improper authorization vulnerability in the Matrix Client-Server API that allows any authenticated local user to delete third-party identifier bindings belonging to other users by submitting an arbitrary address and medium to the account deletion endpoint without ownership verification. Attackers can exploit the unverified Forget3PID handler to remove a victim's email or MSISDN binding and subsequently rebind the address through an identity server to hijack the victim's password reset flow.
Weakness: CWE-639
Which versions are affected by CVE-2026-63095?
How do I fix CVE-2026-63095?
No fix has been published for CVE-2026-63095 yet. Limit exposure of the affected software until one is available.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-63095 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-63095 exists.
Sources
Also known as GHSA-35h8-2q42-v6f5.