Obot OAuth flaw let attackers steal API tokens through audience confusion
- Product
- Obot
- Affected
- Obot <= v0.22.1 with OBOT_SERVER_ENABLE_AUTHENTICATION=true (go/github.com/obot-platform/obot < 0.23.0)
- Fixed in
- v0.23.0
Last verified against sources: October 26, 2026
Am I affected?
Obot: affected Obot <= v0.22.1 with OBOT_SERVER_ENABLE_AUTHENTICATION=true (go/github.com/obot-platform/obot < 0.23.0). Fixed in v0.23.0.
- Check your version: run
go list -m github.com/obot-platform/obot. Versions < 0.23.0 of github.com/obot-platform/obot are affected. [1]
What to do now
- Upgrade to the fixed version: run
go get github.com/obot-platform/obot@v0.23.0(first patched version 0.23.0). [1] - Upgrade to v0.23.0 or later. [1]
General practice, not from the source: if the affected software could read tokens or credentials, rotate them after upgrading; pin versions and review changes before updating tools your agents run.
What happened
- An attacker could register an OAuth client that pointed at a web address the attacker controlled, and no login was needed to do it. [1]
- The approval step was skipped, so a logged-in user who opened a crafted link had an authorization code sent to the attacker's address. [1]
- The attacker traded that code for an access token that carried the victim's full set of groups. [1]
- The token was meant for one MCP server, but it was accepted across the victim's wider API access. [1]
Impact
What was done
- The maintainers released v0.23.0, which adds a consent screen showing the requesting client and the MCP server it wants access to before authorization completes. [1]
- v0.23.0 limits tokens minted by the MCP OAuth flow to only the MCP involved in the request. [1]
- v0.23.0 adds audience validation so these tokens are only accepted for the MCP server they were issued for. [1]
Sources
- GHSA-xwmw-prc4-v3cr — GitHub Advisory Database
Every statement above was checked against these sources before publishing. Spotted an error? Tell us and we will correct it with a dated note.
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Obot OAuth flaw let attackers steal API tokens through audience confusion
Product: Obot | Affected: Obot <= v0.22.1 with OBOT_SERVER_ENABLE_AUTHENTICATION=true (go/github.com/obot-platform/obot < 0.23.0) | Fixed in: v0.23.0
Summary: An attacker could register an OAuth client that pointed at a web address the attacker controlled, and no login was needed to do it.
Source & remediation on AgentArmorHQ: https://agentarmorhq.com/incidents/2026/09/ghsa-xwmw-prc4-v3cr-obotCorrections
Report an error or request a correction. We review requests within 5 business days and add a dated correction note.
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