Improper Check for Unusual or Exceptional Conditions in Junos OS - CVE-2026-57020
Published: July 8, 2026
Vulnerability identifier: #VU137142
CSH Severity: Medium
CVSS v4: 7.1 [CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-57020
CWE-ID: CWE-754
Exploitation vector: Adjecent network
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote non-authenticated attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to improper check for unusual or exceptional conditions error in the packet forwarding engine (pfe). A remote non-authenticated attacker can cause a Denial-of-Service (DoS).
On all QFX10000 platforms in an EVPN-VxLAN scenario, if an attacker sends IPv6 multicast traffic and these packets reach the non-IRB interface of a spine switch, it floods the packet to other spines and all Ethernet Segment Identifier (ESI) leaf switches.
Affected software
Junos OS
How to mitigate CVE-2026-57020
Install updates from vendor's website.
Junos OS - addressed in versions 23.2R2-S7, 23.4R2-S8, 24.2R2-S4, 24.4R2-S4