CVE-2026-70618: Auth Bypass (CVSS 4.3)

Description

Spacebar Server before commit 51da17c contains a missing authorization vulnerability that allows any authenticated user to enumerate complete guild membership by querying the GET /guilds/{guild_id}/roles/{role_id}/member-ids endpoint without guild membership verification. Attackers can exploit the unprotected route handler in the roles member-ids endpoint, which lacks permission checks present in sibling endpoints, to retrieve the full list of member user IDs for any guild on the instance using only a valid bearer token and a known guild ID.

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CVSS v3.1 Score

4.3

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Weakness Type (CWE)

CWE-862 Missing Authorization

References

Other References

https://github.com/spacebarchat/server/commit/51da17cf19d476483ee44e5f832d1ebdcd844f88 https://github.com/spacebarchat/server/security/advisories/GHSA-p5cf-7hg9-gf65 https://www.vulncheck.com/advisories/spacebar-server-missing-authorization-via-member-ids-endpoint

Frequently Asked Questions

What is CVE-2026-70618? +

Spacebar Server before commit 51da17c contains a missing authorization vulnerability that allows any authenticated user to enumerate complete guild membership by querying the GET /guilds/{guild_id}/roles/{role_id}/member-ids endpoint without guild membership verification. Attackers can exploit the unprotected route handler in the roles member-ids endpoint, which lacks permission checks present in sibling endpoints, to retrieve the full list of member user IDs for any guild on the instance using only a valid bearer token and a known guild ID. It has a CVSS v3.1 base score of 4.3 (MEDIUM).

How severe is CVE-2026-70618? +

CVE-2026-70618 has a CVSS v3.1 score of 4.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

How do I check if I'm vulnerable to CVE-2026-70618? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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