Payment-status forgery via localhost Host header
Published Mar 26, 2026 · Updated Mar 26, 2026
Authentication bypass in Yansongda Pay before 3.7.20 allows remote attackers to forge WeChat Pay success callbacks over the network. The verify_wechat_sign() function returns before RSA verification when the PSR-7 URI host derived from the Host header equals localhost. No authentication or user interaction is required, but an upstream proxy that rejects a localhost Host header prevents reachability; exposed applications can mark unpaid orders as paid.
Summary
What happened
Authentication bypass in Yansongda Pay before 3.7.20 allows remote attackers to forge WeChat Pay success callbacks over the network. The verify_wechat_sign() function returns before RSA verification when the PSR-7 URI host derived from the Host header equals localhost. No authentication or user interaction is required, but an upstream proxy that rejects a localhost Host header prevents reachability; exposed applications can mark unpaid orders as paid.
The record
- CVE
- CVE-2026-33661
- Published
- Mar 26, 2026
- Updated
- Mar 26, 2026
- Vendor
- Yansongda
- Product
- Pay
- Classifications
- CWE-290, T1565.002
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 26, 2026CVE publishedPublication date reported by the CVE source.
- Mar 26, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 3.7.20
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Vendor advisory callback proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo