Which versions of OpenClaw are affected by CVE-2026-41395?

OpenClaw versions before 2026.3.28 contain a webhook replay vulnerability that allows attackers to trigger duplicate voice-call processing by manipulating query parameter ordering in captured…. A patch is available.

How to fix or mitigate CVE-2026-41395?

Within 24 hours: Identify all OpenClaw instances in production and document current versions; contact OpenClaw support for patch status and timeline. Within 7 days: Implement webhook signature verification at the application layer to require canonical parameter ordering before processing; enable detailed logging of all webhook processing attempts with source IPs and parameter signatures. Within 30 days: Upgrade to OpenClaw 2026.3.28 or later once available; implement rate-limiting on voice-call webhook endpoints and add request deduplication using cryptographic hashing of the full signed request payload.

OpenClaw CVE-2026-41395

Q: What is the CVSS score of CVE-2026-41395?

CVE-2026-41395 has a CVSS 4.0 base score of 8.2 (High). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 0.0%.

EUVD-2026-26103 HIGH

Missing Cryptographic Step (CWE-325)

2026-04-28 VulnCheck

GHSA-8689-gm9g-jgr6

Authentication Bypass Openclaw

8.2

CVSS 4.0 · NVD

Severity by source

NVD PRIMARY

8.2 HIGH

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Lifecycle Timeline

Patch released

Apr 30, 2026 - 20:45 nvd

Patch available

Apr 28, 2026 - 21:01 EUVD

Re-analysis Queued

Apr 28, 2026 - 20:23 vuln.today

cvss_changed

Analysis Generated

Apr 28, 2026 - 20:04 vuln.today

CVSS changed

Apr 28, 2026 - 19:52 NVD

7.5 (HIGH) 8.2 (HIGH)

EUVD ID Assigned

Apr 28, 2026 - 19:30 euvd

EUVD-2026-26103

Analysis Generated

Apr 28, 2026 - 19:30 vuln.today

CVE Published

Apr 28, 2026 - 18:09 nvd

HIGH 8.2

Blast Radius

ecosystem impact

† from your stack dependencies † transitive graph · vuln.today resolves 4-path depth

3 npm packages depend on openclaw (3 direct, 0 indirect)

Ecosystem-wide dependent count for version 2026.3.28.

DescriptionCVE.org

OpenClaw before 2026.3.28 contains a webhook replay vulnerability in Plivo V3 signature verification that canonicalizes query ordering for signatures but hashes raw URLs for replay detection. Attackers can reorder query parameters to bypass replay cache detection and trigger duplicate voice-call processing with a captured valid signed webhook.

AnalysisAI

Webhook replay attacks in OpenClaw before 2026.3.28 allow remote attackers to trigger duplicate voice-call processing by reordering query parameters in captured Plivo V3 signed webhooks. The vulnerability stems from inconsistent canonicalization: signature verification sorts query parameters before validation, but replay detection hashes the raw URL with original parameter ordering. Attackers possessing a single valid signed webhook can bypass replay cache indefinitely by permuting query string order, causing repeated execution of voice-call workflows without requiring authentication or cryptographic breaks. No public exploit identified at time of analysis, though attack complexity is low (CVSS AC:L) with network vector (AV:N) requiring no privileges (PR:N).

Technical ContextAI

OpenClaw implements Plivo V3 webhook signature verification, a cryptographic mechanism where Plivo signs webhook payloads using HMAC to prove authenticity. The affected product (cpe:2.3:a:openclaw:openclaw:*:*:*:*:*:*:*:*) contains a classic canonicalization vulnerability (CWE-325: Missing Cryptographic Step) in its dual-path processing. The signature verification code canonicalizes query parameters into sorted order before computing the signature hash, following Plivo's specification. However, the replay detection mechanism operates on the raw, unsorted URL string for cache key generation. Since HTTP query parameters are order-independent semantically (e.g., ?a=1&b=2 equals ?b=2&a=1), an attacker can generate N factorial permutations of N parameters from a single captured webhook, each producing a different cache key while maintaining signature validity. This creates an unbounded replay window despite OpenClaw's intended replay protection.

RemediationAI

Upgrade to OpenClaw version 2026.3.28 or later, which addresses the canonicalization inconsistency by applying identical query parameter sorting to both signature verification and replay cache key generation. Vendor advisory with patch details: https://github.com/openclaw/openclaw/security/advisories/GHSA-8689-gm9g-jgr6. If immediate patching is not feasible, implement compensating controls: (1) Add application-level idempotency keys to webhook payloads independent of URL structure, using Plivo's custom header support or payload body fields for unique transaction identifiers; (2) Implement strict webhook source IP allowlisting to Plivo's published IP ranges, reducing attacker's ability to capture valid webhooks, though this does not prevent replay by compromised infrastructure or MITM attackers; (3) Add timestamp-based replay windows (reject webhooks older than 5 minutes) as defense-in-depth, noting this trades protection against clock skew issues. Note that URL normalization at the reverse proxy layer will NOT fix this issue, as the signature must be verified against the original signed URL format. Workarounds reduce but do not eliminate risk until patching.