OpenClaw < 2026.3.28 - Brute Force Attack via Missing Rate Limiting on Webhook Shared Secret Authentication

OpenClaw before 2026.3.28 contains a missing rate limiting vulnerability in the Nextcloud Talk webhook authentication that allows attackers to brute-force weak shared secrets. Attackers who can reach the webhook endpoint can exploit this to forge inbound webhook events by repeatedly attempting authentication without throttling.

OpenClaw before 2026.3.28 contains a missing rate limiting vulnerability in the Nextcloud Talk webhook authentication that allows attackers to brute-force weak shared secrets. Attackers who can reach the webhook endpoint can exploit this to forge inbound webhook events by repeatedly attempting authentication without throttling.

OpenClaw before 2026.3.28 contains a missing rate limiting vulnerability in the Nextcloud Talk webhook authentication that allows attackers to brute-force weak shared secrets. Attackers who can reach the webhook endpoint can exploit this to forge inbound webhook events by repeatedly attempting authentication without throttling.

## Summary Nextcloud Talk webhook signature failures were not throttled even though the integration relies on an operator-configured shared secret that may be weak. ## Impact An attacker who could reach the webhook endpoint could brute-force weak secrets online and then forge inbound webhook events. ## Affected Component `extensions/nextcloud-talk/src/monitor.ts` ## Fixed Versions - Affected: `<= 2026.3.24` - Patched: `>= 2026.3.28` - Latest stable `2026.3.28` contains the fix. ## Fix Fixed by commit `e403decb6e` (`nextcloud-talk: throttle repeated webhook auth failures`). OpenClaw thanks @AntAISecurityLab for reporting.