Vulnerability · Published Apr 23, 2026 · Assigned by VulnCheck
CVE-2026-41351OpenClaw < 2026.3.31 - Webhook Replay Detection Bypass via Base64 Signature Re-encoding
Medium 5.3
In plain English
A medium-severity security flaw in OpenClaw from OpenClaw. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 26% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)5.3Medium
Exploit odds (30 days)0.3%top 73.7% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
OpenClaw before 2026.3.31 contains a replay detection bypass vulnerability in webhook signature handling that treats Base64 and Base64URL encoded signatures as distinct requests. Attackers can re-encode Telnyx webhook signatures to bypass replay detection while maintaining valid signature verification.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | openclaw | 2026.3.31 | GHSA-37v6-fxx8-xjmx |
Affected products (as reported)
Weakness: CWE-294 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
References
- GitHub Security Advisory (GHSA-37v6-fxx8-xjmx) vendor-advisory
- Patch Commit patch
- VulnCheck Advisory: OpenClaw < 2026.3.31 - Webhook Replay Detection Bypass via Base64 Signature Re-encoding third-party-advisory