CVE-2026-33661

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{"affected": [{"affectedData": [{"product": "pay", "vendor": "yansongda", "versions": [{"status": "affected", "version": "< 3.7.20"}]}], "source": "security-advisories@github.com"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:yansongda:pay:*:*:*:*:*:*:*:*", "matchCriteriaId": "EB442148-12BE-4EE8-A5C6-99501BC4C1B2", "versionEndExcluding": "3.7.20", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "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": "2026-06-17T10:37:52.897", "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": "security-advisories@github.com", "type": "Secondary"}, {"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 7.5, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "nvd@nist.gov", "type": "Primary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-33661", "options": [{"exploitation": "poc"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-03-27T14:12:47.859453Z", "version": "2.0.3"}}]}, "published": "2026-03-26T22:16:29.560", "references": [{"source": "security-advisories@github.com", "tags": ["Patch"], "url": "https://github.com/yansongda/pay/commit/26987ebf789f1e7f0a85febb640986ab4289fd7f"}, {"source": "security-advisories@github.com", "tags": ["Release Notes"], "url": "https://github.com/yansongda/pay/releases/tag/v3.7.20"}, {"source": "security-advisories@github.com", "tags": ["Exploit", "Vendor Advisory"], "url": "https://github.com/yansongda/pay/security/advisories/GHSA-q938-ghwv-8gvc"}, {"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "tags": ["Exploit", "Vendor Advisory"], "url": "https://github.com/yansongda/pay/security/advisories/GHSA-q938-ghwv-8gvc"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-290"}], "source": "security-advisories@github.com", "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": "2026-04-02T04:16:38.485386+00:00", "value": {"mitigation_remediation": ["Upgrade the yansongda Pay SDK to version 3.7.20 or later to apply the vendor fix.", "Verify that the application\u2019s callback handler uses the updated verify_wechat_sign logic and that no legacy code bypasses signature checks.", "As a temporary workaround, configure the web server or application firewall to reject or remove Host: localhost headers on the WeChat Pay callback endpoint, or restrict the endpoint to trusted IPs.", "Monitor transaction logs for unexpected payment confirmations that could indicate crafted callback requests."], "summary": {"action": "Immediate Patch", "impact": "Authentication Bypass: Forged Payment Success"}, "threat_synthesis": {"affected_systems": "The vulnerability affects any installation of the yansongda Pay SDK older than version 3.7.20. When this library exposes a WeChat Pay callback endpoint to external traffic, the skip logic can be triggered by a simple HTTP header manipulation.", "description_and_impact": "An open\u2011source payment SDK for Chinese payment services contains a flaw in the signature verification routine that skips all checks when the HTTP Host header is set to localhost. An attacker who can send a crafted request to the WeChat Pay callback endpoint with a Host: localhost header can bypass the RSA signature verification entirely, allowing the attacker to forge a payment success notification and cause an application to record an order as paid without any real transaction.", "risk_and_exploitability": "With a CVSS score of 8.6 the flaw is considered high severity, yet its EPSS score is under 1% and it is not listed in the CISA KEV catalog, indicating low current exploitation likelihood. The attack vector is network\u2011based, requiring only a single crafted HTTP request. Because the bypass depends solely on the Host header, it can be performed remotely without escalating privileges, but the impact is the potential to manipulate financial transactions."}}}}, "created": "2026-03-27T08:31:50.276432+00:00", "updated": "2026-04-02T07:56:18.545299+00:00", "vendors": ["yansongda", "yansongda$PRODUCT$pay"]}