Description
Spacebar Server before commit dcfd910 contains a missing authorization vulnerability that allows any authenticated attacker to add themselves to arbitrary group DM channels by sending a PUT request to the channels recipient endpoint without membership verification. Attackers can exploit the unguarded PUT /channels/{channel_id}/recipients/{user_id} handler to join private group DMs, read complete message history, post messages as a participant, and force-add third-party users without their consent.
Severity (CVSS)
| Base score | 8.6 |
|---|---|
| Severity | High |
| Version | CVSS 4.0 |
| Vector | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N |
| Provided by | CNA |
Weaknesses
- CWE-862 — Missing Authorization
Affected products
| Vendor | Product | Versions |
|---|---|---|
| Spacebar Server | Spacebar Server | 0 to <=dcfd91035e3da42abf5f32d8d86a35219225b3d4 |
References
- https://github.com/spacebarchat/server/security/advisories/GHSA-g38j-78fh-jm74 (vendor-advisory)
- https://github.com/spacebarchat/server/commit/dcfd91035e3da42abf5f32d8d86a35219225b3d4 (patch)
- https://www.vulncheck.com/advisories/spacebar-server-missing-authorization-via-group-dm-recipient-endpoint (third-party-advisory)
Generated from the official CVE List on 06 Aug 2026 07:06 UTC.