Obot OAuth dynamic client registration token theft via audience confusion

Severity: high · CVSS 8.8 · Published 2026-09-18

Obot is an open-source platform for managing API integrations and workflows. An attacker could trick a logged-in user into clicking a malicious link to steal their API access token, allowing the attacker to read or modify the victim's resources until the token is revoked. No special privileges or technical sophistication are required—the attack succeeds if a victim simply clicks a link.

Technologies: github.com/obot-platform/obot (Go). Vendors: Go.

Quick answers

Is This vulnerability exploited in the wild?
No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.
How severe is This vulnerability?
High severity, with a CVSS score of 8.8, published 18 September 2026.
Which products and versions are affected?
github.com/obot-platform/obot (Go) < 0.23.0.
Is there a fix for This vulnerability?
A patch was published on 2026-09-18: Fix released in v0.23.0 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is This vulnerability attacked?
It is attacked over the network.
Am I affected?
Check whether you run github.com/obot-platform/obot (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The vulnerability stems from three combined flaws in OAuth dynamic client registration: (1) unauthenticated attackers could register OAuth clients with arbitrary redirect URIs, (2) the authorization flow auto-completed without a consent screen for logged-in users, and (3) issued tokens contained the victim's full group set in the JWT but lacked proper audience validation, allowing tokens scoped for one MCP server to be accepted across the victim's broader API access. An attacker crafts an authorization URL, tricks a logged-in victim into visiting it, and receives an authorization code redirected to the attacker's domain, which is exchanged for an access token. The fix in v0.23.0+ adds a consent screen, restricts MCP token scope to the specific server, and enforces JWT audience validation.

Affected products

  • Obot Obot <= v0.22.1

Timeline

  • 2026-09-18: disclosed: Security advisory published
  • 2026-09-18: patched: Fix released in v0.23.0

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