Is there a patch available for EUVD-2026-25335?

Yes, a patch is available for EUVD-2026-25335. Update the affected software to the latest version immediately.

OpenClaw EUVD-2026-25335

Q: What is the CVSS score of EUVD-2026-25335?

EUVD-2026-25335 has a CVSS 4.0 base score of 6.3 (Medium). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/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%.

| CVE-2026-41351 MEDIUM

Authentication Bypass by Capture-replay (CWE-294)

2026-04-23 VulnCheck

GHSA-m958-864j-xq5w

Authentication Bypass Openclaw

6.3

CVSS 4.0 · NVD

Severity by source

NVD PRIMARY

6.3 MEDIUM

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/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

vuln.today AI

4.8 MEDIUM

AC:H reflects the CVSS 4.0 AT:P prerequisite of capturing a prior valid webhook; C:L/I:L from duplicate event processing; no availability impact.

3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

4.0 AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

Primary rating from NVD.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Lifecycle Timeline

Source Code Evidence Fetched

Jul 24, 2026 - 03:22 vuln.today

Analysis Generated

Jul 24, 2026 - 03:22 vuln.today

CVSS changed

Apr 23, 2026 - 22:28 NVD

5.3 (MEDIUM) 6.3 (MEDIUM)

EUVD ID Assigned

Apr 23, 2026 - 22:15 euvd

EUVD-2026-25335

Patch released

Apr 23, 2026 - 22:15 nvd

Patch available

CVE Published

Apr 23, 2026 - 21:58 nvd

MEDIUM 6.3

Blast Radius

ecosystem impact

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

1 npm packages depend on openclaw (1 direct, 0 indirect)

Ecosystem-wide dependent count for version 2026.3.31.

DescriptionCVE.org

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.

AnalysisAI

Replay detection bypass in the OpenClaw npm package (versions ≤ 2026.3.28) allows an attacker who has previously captured a valid Telnyx-signed webhook to re-encode the Ed25519 signature from standard Base64 to Base64URL and resubmit the payload as an apparently unreplayed request. Because Ed25519 cryptographic verification operates on the decoded byte sequence, both encodings pass signature validation; only the replay cache lookup - keyed on the raw uncanonicalised header string - is defeated, enabling duplicate event processing. No public exploit has been identified at time of analysis and EPSS stands at 0.03% (8th percentile), consistent with SSVC Exploitation: none and the maintainer's own normalized severity of low.

Technical ContextAI

OpenClaw is an npm package (cpe:2.3:a:openclaw:openclaw:*:*:*:*:*:*:*:*) providing a Telnyx voice-call webhook integration via its extensions/voice-call module. Telnyx authenticates outbound webhooks with an Ed25519 signature transmitted in the telnyx-signature-ed25519 HTTP header. OpenClaw's replay detection computes a SHA-256 key from the raw header value, timestamp, and body to identify already-seen requests. The flaw (CWE-294, Authentication Bypass by Capture-Replay) arises because Base64 and Base64URL are byte-equivalent encodings differing only in the use of - vs +, _ vs /, and the omission of trailing = padding; the Ed25519 verifier decodes either form identically, but the string-keyed replay cache treats them as distinct entries. The fix - commit ad77666054651c1fd77b1dc60fd6a8db6600a29a - adds a canonicalization step that converts signatureBuffer.toString('base64') before SHA-256 hashing, ensuring both encoding variants map to the same replay cache key.

RemediationAI

Upgrade the openclaw npm package to version 2026.3.31 or later - confirmed by GHSA as the first patched release, containing fix commit ad77666054651c1fd77b1dc60fd6a8db6600a29a (merged 2026-03-30). The advisory is at https://github.com/openclaw/openclaw/security/advisories/GHSA-37v6-fxx8-xjmx. Where an immediate upgrade is not feasible, deploy an ingress reverse proxy or middleware rule that normalizes every inbound telnyx-signature-ed25519 header to canonical Base64 (replace - with +, _ with /, and restore = padding to the correct length) before requests reach the application, effectively replicating the canonicalization fix externally; note this adds operational complexity and must be applied at every ingress point serving Telnyx webhooks. No other configuration toggle or feature disable is available because replay protection is always active in the affected code path.