CVE-2026-63095

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.

References

https://www.vulncheck.com/advisories/dendrite-improper-authorization-via-post-account-3pid-delete-endpoint

https://github.com/geo-chen/oss/blob/main/dendrite.md#finding-1-idor-in-post-account3piddelete-allows-any-authenticated-user-to-remove-any-other-users-third-party-identifier

Details

Source: Mitre, NVD

Risk Information

CVSS v2

CVSS v3

CVSS v4