Junglewise Threat Intelligence

OpenClaw replay protection bypass in Plivo V2 signature verification

Severity: medium · CVSS 6.5 · Published 2026-04-10

Technologies: Openclaw. Vendors: Openclaw.

Executive brief

OpenClaw is a library used for handling voice call webhooks. A security flaw in its signature verification process allows attackers to bypass replay protections by slightly modifying web addresses. This could allow an attacker to resubmit previously authorized requests, potentially leading to unauthorized actions or data manipulation within the voice call system.

Technical details

OpenClaw versions prior to 2026.3.23 are vulnerable to an authentication bypass via capture-replay (CWE-294). The root cause is located in the Plivo V2 signature verification logic within 'extensions/voice-call/src/webhook-security.ts'. While the signature validation correctly canonicalizes the base URL, the replay key derivation incorrectly used the full verification URL including query strings. This discrepancy allows an attacker to modify unsigned query parameters to generate a new 'verifiedRequestKey' for a previously signed request, effectively bypassing replay protection. The vulnerability is exploitable over the network without authentication, though it requires the attacker to capture a valid signed request first. The issue is fixed in version 2026.3.23 by ensuring replay keys are derived from the canonicalized base URL and nonce.

Affected products

  • OpenClaw openclaw < 2026.3.23

Timeline

  • 2026-03-24: advisory: Original advisory GHSA-cg6c-q2hx-69h7 published
  • 2026-04-09: disclosed: CVE-2026-35618 published to NVD
  • 2026-04-10: advisory: Duplicate advisory GHSA-j56c-wpqm-h24x published and withdrawn
  • 2026-03-23: patched: Version 2026.3.23 released with fix

References

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