postfix-mta-sts-resolver Algorithm Downgrade vulnerability
Incorrect query parsing
Impact
All users of versions prior to 0.5.1 can receive incorrect response from daemon under rare conditions, rendering downgrade of effective STS policy.
Patches
Problem has been patched in version 0.5.1
Workarounds
Users may remediate this vulnerability without upgrading by applying these patches to older suppoorted versions.
For more information
If you have any questions or comments about this advisory:
- Open an issue in postfix-mta-sts-resolver repo
- Email me at vladislav at vm-0 dot com
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | postfix-mta-sts-resolver | < 0.5.1 | 0.5.1 |
References
- https://github.com/Snawoot/postfix-mta-sts-resolver/security/advisories/GHSA-h92m-42h4-82f6
- https://gist.github.com/Snawoot/b9da85d6b26dea5460673b29df1adc6b
- https://nvd.nist.gov/vuln/detail/CVE-2019-16791
- https://github.com/Snawoot/postfix-mta-sts-resolver
- https://github.com/pypa/advisory-database/tree/main/vulns/postfix-mta-sts-resolver/PYSEC-2020-174.yaml
- CVSS vector
CVSS:3.1/AV:L/AC:H/PR:H/UI:R/S:C/C:H/I:H/A:N- Weakness (CWE)
CWE-757- Platform
- Python (PyPI)
- Package
postfix-mta-sts-resolver- Disclosed
- 05.07.2019
- Updated
- 11.10.2026 15:17
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2020-174 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-h92m-42h4-82f6 - CC BY 4.0
Vulnerability history: postfix-mta-sts-resolver
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
This is the only known vulnerability of this package.
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