{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-41351", "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "state": "PUBLISHED", "assignerShortName": "VulnCheck", "dateReserved": "2026-04-20T14:07:26.648Z", "datePublished": "2026-04-23T21:58:11.440Z", "dateUpdated": "2026-04-24T13:33:45.799Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "shortName": "VulnCheck", "dateUpdated": "2026-04-23T21:58:11.440Z"}, "title": "OpenClaw < 2026.3.31 - Webhook Replay Detection Bypass via Base64 Signature Re-encoding", "descriptions": [{"lang": "en", "value": "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."}], "tags": ["x_open-source"], "datePublic": "2026-03-31T00:00:00.000Z", "problemTypes": [{"descriptions": [{"lang": "en", "cweId": "CWE-294", "description": "CWE-294 Authentication Bypass by Capture-replay", "type": "CWE"}]}], "affected": [{"vendor": "OpenClaw", "product": "OpenClaw", "defaultStatus": "unaffected", "packageURL": "pkg:npm/openclaw", "versions": [{"version": "0", "status": "affected", "versionType": "semver", "lessThan": "2026.3.31"}, {"version": "2026.3.31", "status": "unaffected", "versionType": "semver"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:openclaw:openclaw:*:*:*:*:*:node.js:*:*", "versionEndExcluding": "2026.3.31"}]}]}], "metrics": [{"format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}], "cvssV4_0": {"attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "LOW", "subConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "subIntegrityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "version": "4.0", "baseSeverity": "MEDIUM", "baseScore": 6.3, "vectorString": "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"}}, {"format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}], "cvssV3_1": {"attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "NONE", "availabilityImpact": "NONE", "version": "3.1", "baseSeverity": "MEDIUM", "baseScore": 5.3, "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"}}], "references": [{"url": "https://github.com/openclaw/openclaw/security/advisories/GHSA-37v6-fxx8-xjmx", "name": "GitHub Security Advisory (GHSA-37v6-fxx8-xjmx)", "tags": ["vendor-advisory"]}, {"url": "https://github.com/openclaw/openclaw/commit/ad77666054651c1fd77b1dc60fd6a8db6600a29a", "name": "Patch Commit", "tags": ["patch"]}, {"name": "VulnCheck Advisory: OpenClaw < 2026.3.31 - Webhook Replay Detection Bypass via Base64 Signature Re-encoding", "tags": ["third-party-advisory"], "url": "https://www.vulncheck.com/advisories/openclaw-webhook-replay-detection-bypass-via-base64-signature-re-encoding"}], "credits": [{"lang": "en", "value": "AntAISecurityLab", "type": "reporter"}], "x_generator": {"engine": "vulncheck"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-04-24T13:33:40.282038Z", "id": "CVE-2026-41351", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "partial"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-04-24T13:33:45.799Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-41351", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "partial"}], "version": "2.0.3", "timestamp": "2026-04-24T13:33:40.282038Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-04-24T13:33:43.081Z"}}], "cna": {"tags": ["x_open-source"], "title": "OpenClaw < 2026.3.31 - Webhook Replay Detection Bypass via Base64 Signature Re-encoding", "credits": [{"lang": "en", "type": "reporter", "value": "AntAISecurityLab"}], "metrics": [{"format": "CVSS", "cvssV4_0": {"Safety": "NOT_DEFINED", "version": "4.0", "Recovery": "NOT_DEFINED", "baseScore": 6.3, "Automatable": "NOT_DEFINED", "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "valueDensity": "NOT_DEFINED", "vectorString": "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", "exploitMaturity": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "userInteraction": "NONE", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "LOW", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "scenarios": [{"lang": "en", "value": "GENERAL"}]}, {"format": "CVSS", "cvssV3_1": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 5.3, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "LOW"}, "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "affected": [{"vendor": "OpenClaw", "product": "OpenClaw", "versions": [{"status": "affected", "version": "0", "lessThan": "2026.3.31", "versionType": "semver"}, {"status": "unaffected", "version": "2026.3.31", "versionType": "semver"}], "packageURL": "pkg:npm/openclaw", "defaultStatus": "unaffected"}], "datePublic": "2026-03-31T00:00:00.000Z", "references": [{"url": "https://github.com/openclaw/openclaw/security/advisories/GHSA-37v6-fxx8-xjmx", "name": "GitHub Security Advisory (GHSA-37v6-fxx8-xjmx)", "tags": ["vendor-advisory"]}, {"url": "https://github.com/openclaw/openclaw/commit/ad77666054651c1fd77b1dc60fd6a8db6600a29a", "name": "Patch Commit", "tags": ["patch"]}, {"url": "https://www.vulncheck.com/advisories/openclaw-webhook-replay-detection-bypass-via-base64-signature-re-encoding", "name": "VulnCheck Advisory: OpenClaw < 2026.3.31 - Webhook Replay Detection Bypass via Base64 Signature Re-encoding", "tags": ["third-party-advisory"]}], "x_generator": {"engine": "vulncheck"}, "descriptions": [{"lang": "en", "value": "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."}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-294", "description": "CWE-294 Authentication Bypass by Capture-replay"}]}], "cpeApplicability": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:openclaw:openclaw:*:*:*:*:*:node.js:*:*", "vulnerable": true, "versionEndExcluding": "2026.3.31"}], "operator": "OR"}]}], "providerMetadata": {"orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "shortName": "VulnCheck", "dateUpdated": "2026-04-23T21:58:11.440Z"}}}, "cveMetadata": {"cveId": "CVE-2026-41351", "state": "PUBLISHED", "dateUpdated": "2026-04-24T13:33:45.799Z", "dateReserved": "2026-04-20T14:07:26.648Z", "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "datePublished": "2026-04-23T21:58:11.440Z", "assignerShortName": "VulnCheck"}, "dataVersion": "5.2"}

{"configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:openclaw:openclaw:*:*:*:*:*:node.js:*:*", "matchCriteriaId": "35B1FB5C-EA5A-4095-9226-F947A9B3B984", "versionEndExcluding": "2026.3.31", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "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."}], "id": "CVE-2026-41351", "lastModified": "2026-04-28T18:56:43.543", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 5.3, "baseSeverity": "MEDIUM", "confidentialityImpact": "LOW", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 1.4, "source": "disclosure@vulncheck.com", "type": "Primary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 6.3, "baseSeverity": "MEDIUM", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "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", "version": "4.0", "vulnAvailabilityImpact": "NONE", "vulnConfidentialityImpact": "LOW", "vulnIntegrityImpact": "NONE", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "disclosure@vulncheck.com", "type": "Secondary"}]}, "published": "2026-04-23T22:16:42.160", "references": [{"source": "disclosure@vulncheck.com", "tags": ["Patch"], "url": "https://github.com/openclaw/openclaw/commit/ad77666054651c1fd77b1dc60fd6a8db6600a29a"}, {"source": "disclosure@vulncheck.com", "tags": ["Vendor Advisory"], "url": "https://github.com/openclaw/openclaw/security/advisories/GHSA-37v6-fxx8-xjmx"}, {"source": "disclosure@vulncheck.com", "tags": ["Third Party Advisory"], "url": "https://www.vulncheck.com/advisories/openclaw-webhook-replay-detection-bypass-via-base64-signature-re-encoding"}], "sourceIdentifier": "disclosure@vulncheck.com", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-294"}], "source": "disclosure@vulncheck.com", "type": "Primary"}]}

{}

{"affected": [{"configurations": [{"platform": ["node.js"], "status": "affected", "versions": {"scheme": "semver", "value": "[0,2026.3.31)"}}, {"platform": ["node.js"], "status": "unaffected", "versions": {"scheme": "semver", "value": "[2026.3.31,*]"}}], "enrichment": {"confidence": 90.0, "confidence_source": "inferred", "scores": [{"score": 90.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "product": "openclaw", "vendor": "openclaw"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,2026.3.31)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[2026.3.31,*]"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "OpenClaw", "source": "cna", "vendor": "OpenClaw"}, "product": "openclaw", "vendor": "openclaw"}], "analysis": {"en": {"generated_at": "2026-04-28T14:37:10.952682+00:00", "value": {"mitigation_remediation": ["Deploy the official OpenClaw update to version 2026.3.31 or newer.", "If an update cannot be applied immediately, restrict access to the webhook endpoint using IP whitelisting for Telnyx\u2019s known inbound addresses.", "Implement strict canonical Base64 decoding in the signature verification code so that Base64 and Base64URL encodings are treated as equivalent, preventing replay of re\u2011encoded signatures."], "summary": {"action": "Immediately Patch", "impact": "Replay Attack"}, "threat_synthesis": {"affected_systems": "The vulnerability affects the OpenClaw product released by OpenClaw in all versions prior to 2026.3.31. No specific patch versions are provided beyond the statement that upgrading beyond 2026.3.31 resolves the issue.", "description_and_impact": "OpenClaw versions prior to 2026.3.31 allow an attacker to bypass the webhook replay detection mechanism by re-encoding Telnyx webhook signatures from Base64 to Base64URL or vice\u2011versa. The signature verification logic treats these two encodings as distinct, so an attacker can replay a verified request without triggering the replay guard. The result is that the same webhook payload can be processed multiple times, potentially leading to duplicate operations, double charges, or other unintended side effects. The weakness is a cryptographic parameter handling issue (CWE-294).", "risk_and_exploitability": "The CVSS score of 6.3 indicates moderate severity. The EPSS score is below 1%, implying a very low likelihood of widespread exploitation at present. The vulnerability is not listed in CISA\u2019s KEV catalog, suggesting that no widespread, targeted attacks have been observed yet. However, if attackers obtain a valid webhook signature for a legitimate Telnyx integration, they can easily re\u2011encode it to replay the message; therefore the attack can be performed by anyone who can capture the signature during normal operation. The described exploit path requires only the ability to see or capture a legitimate webhook request, then re\u2011encode its signature before re\u2011sending it to the OpenClaw webhook endpoint."}}}}, "created": "2026-04-28T01:30:17.724118+00:00", "updated": "2026-04-28T14:45:16.190523+00:00", "vendors": ["openclaw", "openclaw$PRODUCT$openclaw"]}