Improper Check for Unusual or Exceptional Conditions in Junos OS - CVE-2026-57031
Published: July 8, 2026
Vulnerability identifier: #VU137148
CSH Severity: Medium
CVSS v4: 5.3 [CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-57031
CWE-ID: CWE-754
Exploitation vector: Adjecent network
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to bypass configured firewall filters.
The vulnerability exists due to improper check for unusual or exceptional conditions in the packet forwarding engine (PFE) when handling traffic from subscribers configured on static interfaces with an input filter. A remote attacker can send network traffic to bypass configured firewall filters.
Only MX Series devices with MPC10/11, LC4800/9600/4802, or MX304 hardware are affected, and exposure requires a configuration for static subscribers with an input filter.
Affected software
Junos OS
How to mitigate CVE-2026-57031
Install security update from vendor's website.
Junos OS - addressed in versions 23.2R2-S7, 23.4R2-S7, 24.2R2-S3, 24.4R2-S2, 25.2R2, 25.4R1