CVE-2026-70617
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…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.23%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 4.0
- 8.6 HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.23% probability · 14th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-862
- Source
- disclosure@vulncheck.com
References
- https://github.com/spacebarchat/server/commit/dcfd91035e3da42abf5f32d8d86a35219225b3d4
- https://github.com/spacebarchat/server/security/advisories/GHSA-g38j-78fh-jm74
- https://www.vulncheck.com/advisories/spacebar-server-missing-authorization-via-group-dm-recipient-endpoint
- https://github.com/spacebarchat/server/security/advisories/GHSA-g38j-78fh-jm74
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.