{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-33661", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-03-23T15:23:42.219Z", "datePublished": "2026-03-26T21:05:22.607Z", "dateUpdated": "2026-03-27T20:00:56.285Z"}, "containers": {"cna": {"title": "WeChat Pay callback signature verification bypassed when Host header is localhost", "problemTypes": [{"descriptions": [{"cweId": "CWE-290", "lang": "en", "description": "CWE-290: Authentication Bypass by Spoofing", "type": "CWE"}]}], "metrics": [{"cvssV3_1": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 8.6, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "CHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N", "version": "3.1"}}], "references": [{"name": "https://github.com/yansongda/pay/security/advisories/GHSA-q938-ghwv-8gvc", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/yansongda/pay/security/advisories/GHSA-q938-ghwv-8gvc"}, {"name": "https://github.com/yansongda/pay/commit/26987ebf789f1e7f0a85febb640986ab4289fd7f", "tags": ["x_refsource_MISC"], "url": "https://github.com/yansongda/pay/commit/26987ebf789f1e7f0a85febb640986ab4289fd7f"}, {"name": "https://github.com/yansongda/pay/releases/tag/v3.7.20", "tags": ["x_refsource_MISC"], "url": "https://github.com/yansongda/pay/releases/tag/v3.7.20"}], "affected": [{"vendor": "yansongda", "product": "pay", "versions": [{"version": "< 3.7.20", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-03-26T21:05:22.607Z"}, "descriptions": [{"lang": "en", "value": "Pay is an open-source payment SDK extension package for various Chinese payment services. Prior to version 3.7.20, the `verify_wechat_sign()` function in `src/Functions.php` unconditionally skips all signature verification when the PSR-7 request reports `localhost` as the host. An attacker can exploit this by sending a crafted HTTP request to the WeChat Pay callback endpoint with a `Host: localhost` header, bypassing the RSA signature check entirely. This allows forging fake WeChat Pay payment success notifications, potentially causing applications to mark orders as paid without actual payment. Version 3.7.20 fixes the issue."}], "source": {"advisory": "GHSA-q938-ghwv-8gvc", "discovery": "UNKNOWN"}}, "adp": [{"references": [{"url": "https://github.com/yansongda/pay/security/advisories/GHSA-q938-ghwv-8gvc", "tags": ["exploit"]}], "metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-03-27T14:12:47.859453Z", "id": "CVE-2026-33661", "options": [{"Exploitation": "poc"}, {"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": "2026-03-27T20:00:56.285Z"}}]}}

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{"cveTags": [], "descriptions": [{"lang": "en", "value": "Pay is an open-source payment SDK extension package for various Chinese payment services. Prior to version 3.7.20, the `verify_wechat_sign()` function in `src/Functions.php` unconditionally skips all signature verification when the PSR-7 request reports `localhost` as the host. An attacker can exploit this by sending a crafted HTTP request to the WeChat Pay callback endpoint with a `Host: localhost` header, bypassing the RSA signature check entirely. This allows forging fake WeChat Pay payment success notifications, potentially causing applications to mark orders as paid without actual payment. Version 3.7.20 fixes the issue."}, {"lang": "es", "value": "Pay es un paquete de extensi\u00f3n de SDK de pago de c\u00f3digo abierto para varios servicios de pago chinos. Antes de la versi\u00f3n 3.7.20, la funci\u00f3n `verify_wechat_sign()` en `src/Functions.php` omite incondicionalmente toda la verificaci\u00f3n de firma cuando la solicitud PSR-7 informa localhost como el host. Un atacante puede explotar esto enviando una solicitud HTTP manipulada al endpoint de callback de WeChat Pay con un encabezado Host: localhost, eludiendo por completo la verificaci\u00f3n de firma RSA. Esto permite falsificar notificaciones de \u00e9xito de pago falsas de WeChat Pay, lo que podr\u00eda hacer que las aplicaciones marquen los pedidos como pagados sin un pago real. La versi\u00f3n 3.7.20 corrige el problema."}], "id": "CVE-2026-33661", "lastModified": "2026-03-27T20:16:32.600", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 8.6, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "CHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 4.0, "source": "[email protected]", "type": "Secondary"}]}, "published": "2026-03-26T22:16:29.560", "references": [{"source": "[email protected]", "url": "https://github.com/yansongda/pay/commit/26987ebf789f1e7f0a85febb640986ab4289fd7f"}, {"source": "[email protected]", "url": "https://github.com/yansongda/pay/releases/tag/v3.7.20"}, {"source": "[email protected]", "url": "https://github.com/yansongda/pay/security/advisories/GHSA-q938-ghwv-8gvc"}, {"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "url": "https://github.com/yansongda/pay/security/advisories/GHSA-q938-ghwv-8gvc"}], "sourceIdentifier": "[email protected]", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-290"}], "source": "[email protected]", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,3.7.20)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "cna", "scores": [{"score": 100.0, "source": "cna"}]}, "original": {"product": "pay", "source": "cna", "vendor": "yansongda"}, "product": "pay", "vendor": "yansongda"}], "analysis": {"en": {"generated_at": "2026-03-26T22:52:42.618422+00:00", "value": {"mitigation_remediation": ["Upgrade yansongda:pay to version 3.7.20 or later to restore correct signature verification.", "Configure the application to reject callback requests that contain an internal host name such as \"localhost\".\n", "Audit the dependency tree to ensure no older version of the Pay SDK is used at runtime.\n", "Monitor payment confirmation logs for anomalous entries and investigate any suspicious orders promptly."], "summary": {"action": "Immediate Patch", "impact": "Unauthorized Payment Confirmation"}, "threat_synthesis": {"affected_systems": "The vulnerability affects the open\u2011source Pay SDK, known as yansongda:pay, used to integrate Chinese payment services.\nVersions older than 3.7.20 contain the flaw.\nThe fix was released in 3.7.20, where the verification logic was corrected to reject requests with a Host header of \"localhost\".\n", "description_and_impact": "The Pay SDK\u2019s verification function skips the RSA signature check whenever the HTTP request reports a Host header of \"localhost\".\nThis flaw allows an attacker to post a crafted callback to the WeChat Pay notification endpoint, tricking the application into accepting a fake success message.\nThe result is that orders can be marked as paid without an actual payment, potentially leading to financial loss due to fraudulent orders.\nThe weakness is a signature bypass and corresponds to a credential verification failure.\n", "risk_and_exploitability": "The flaw carries a CVSS score of 8.6, indicating high severity.\nAn attacker only needs the ability to send an HTTP request to the callback endpoint; local code execution or privileged access is not required.\nExploit probability data is not available.\nThe vulnerability has not been listed in known exploited vulnerabilities catalogs.\nThe attack vector is remote, exploiting a HTTP callback endpoint by manipulating the Host header to \"localhost\".\n"}}}}, "created": "2026-03-27T08:31:50.276432+00:00", "updated": "2026-03-27T09:23:17.364649+00:00", "vendors": ["yansongda", "yansongda$PRODUCT$pay"]}