Capgo bundle promotion API channel RBAC deny override bypass

Capgo (Cap-go/capgo.app) server backend Supabase functions contain an incorrect authorization flaw in the API-key bundle promotion path. The PUT /bundle endpoint, available to "all" and "write" API keys, dispatches to setChannel, which authorizes with checkPermission(c, 'channel.promote_bundle', { appId: body.app_id }) and omits the request's channel_id. Because the omitted scope field is passed to rbac_check_permission_direct as SQL NULL, and channel-scope override evaluation is gated on p_channel_id IS NOT NULL, per-channel allow/deny overrides are never evaluated. A principal holding app-level channel.promote_bundle (granted by default to the app_developer and app_uploader roles) can therefore promote a bundle to a channel for which an explicit per-channel deny override exists, updating public.channels.version for the supplied channel_id; the target channel is only validated after authorization. The issue is confirmed on main at commit de66fa51e7ff2f50283cc1455c3d80ab3eb0ae43 and likely earlier versions; no patched version is known at the time of publication.

Source published

26 Sep 2026 13:23:04 UTC

Source modified

30 Sep 2026 17:20:12 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

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CVSS 4.0 · 7.2 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS 3.1 · 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H