CVE-2026-28449: OpenClaw < 2026.2.25 - Webhook Replay Attack via Missing Durable Replay Suppression

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-03-19 · updated 2026-06-17
Weakness: CWE-294

Description

OpenClaw versions prior to 2026.2.25 lack durable replay state for Nextcloud Talk webhook events, allowing valid signed webhook requests to be replayed without suppression. Attackers can capture and replay previously valid signed webhook requests to trigger duplicate inbound message processing and cause integrity or availability issues.

Affected products

OpenClaw: before 2026.2.25 — fixed in 2026.2.25

How to fix

Upgrade to a fixed version: OpenClaw 2026.2.25. Check the vendor advisory for mitigations.

References

https://github.com/openclaw/openclaw/commit/d512163d686ad6741783e7119ddb3437f493dbbc
https://github.com/openclaw/openclaw/security/advisories/GHSA-r9q5-c7qc-p26w
https://www.vulncheck.com/advisories/openclaw-webhook-replay-attack-via-missing-durable-replay-suppression

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