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

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.

CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

释放后使用

Juniper Networks Junos OS 安全漏洞

Juniper Networks Junos OS是美国瞻博网络（Juniper Networks）公司的一套专用于该公司的硬件设备的网络操作系统。该操作系统提供了安全编程接口和Junos SDK。 Juniper Networks Junos OS和Junos OS Evolved存在安全漏洞，该漏洞源于2层地址学习守护程序l2ald中存在释放后重用漏洞。受影响的产品和版本：Junos OS 20.4R3-S8之前版本，21.2R3-S6之前版本，21.3R3-S5之前版本，21.4R3-S4之前版本，

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