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Vulnerabilities

Vulnerability · CVE-2026-33661

Pay is an open-source payment SDK extension package for various Chinese payment services.

Published Mar 26, 2026 · catalog updated Jun 17, 2026 · Pay is an open-source

Check if you run it

No confirmed exploitation is on record for CVE-2026-33661. EPSS is 0.67%. Act only if a listed version of Pay is an open-source is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Pay is an open-source).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High7.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.67%
Remediation
Advisory link
Affected products
cpe yansongda/pay

Pay is an open-source payment SDK extension package for various Chinese payment services. Prior to version 3.7.20, the function in unconditionally skips all signature verification when the PSR-7 request reports as the host. An attacker can exploit this by sending a crafted HTTP request to the WeChat Pay callback endpoint with a 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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe yansongda/payversion unspecified

How to fix CVE-2026-33661

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-33661. EPSS is 0.67%. Act only if a listed version of Pay is an open-source is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-290: Authentication Bypass by Spoofing. EPSS 0.67%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 26, 2026 · NIST NVD

    Detected

    Pay is an open-source payment SDK extension package for various Chinese payment services. Prior to version 3.7.20, the function in unconditionally skips all signature verification when the PSR-7 request reports as the host. An attacker can exploit this by sending a crafted HTTP request to the WeChat Pay callback endpoint with a header, bypassing the RSA signature check entirely. This allows forgin

  2. Jun 17, 2026 · NIST NVD

    Updated

    Pay is an open-source payment SDK extension package for various Chinese payment services. Prior to version 3.7.20, the function in unconditionally skips all signature verification when the PSR-7 request reports as the host. An attacker can exploit this by sending a crafted HTTP request to the WeChat Pay callback endpoint with a header, bypassing the RSA signature check entirely. This allows forgin

Sources

  • CVE.orgVulnerability recordCVE-2026-33661

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-33661

    30-day exploitation probability 0.7%

    first.org
  • NIST NVDVulnerability recordCVE-2026-33661

    Pay is an open-source payment SDK extension package for various Chinese payment services. Prior to version 3.7.20, the function in unconditionally skips all signature verification when the PSR-7 request reports as the host. A

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.