Junos OS: MX Series: For subscribers configured on static interfaces, input filters are not in effect
Summary
| CVE | CVE-2026-57031 |
|---|---|
| State | PUBLISHED |
| Assigner | juniper |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-07-09 22:17:08 UTC |
| Updated | 2026-07-10 17:49:57 UTC |
| Description | An Improper Check for Unusual or Exceptional Conditions vulnerability in the packet forwarding engine (PFE) of Juniper Networks Junos OS on MX Series allows adjacent subscribers to bypass configured firewall filters. On MX Series devices with MPC10/11, LC4800/9600, and MX304 with subscribers configured on static interfaces, ingress firewall filters are not enforced, so that neither protocol level nor upstream bandwidth limitation are in effect. This issue affects Junos OS on MX with MPC10/11, LC4800/9600/4802, and MX304: * 23.2 versions from 23.2R2-S1 before 23.2R2-S7, * 23.4 versions from 23.4R2 before 23.4R2-S7, * 24.2 versions before 24.2R2-S3, * 24.4 versions before 24.4R2-S2, * 25.2 versions before 25.2R2. |
Risk And Classification
Primary CVSS: v4.0 5.3 MEDIUM from [email protected]
CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:X/V:X/RE:M/U:X
EPSS: 0.002380000 probability, percentile 0.148130000 (date 2026-07-11)
Problem Types: CWE-754 | CWE-754 CWE-754 Improper Check for Unusual or Exceptional Conditions
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | [email protected] | Secondary | 5.3 | MEDIUM | CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N/E:X/C... |
| 4.0 | CNA | CVSS | 5.3 | MEDIUM | CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N/AU:Y/... |
| 3.1 | [email protected] | Secondary | 4.7 | MEDIUM | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N |
| 3.1 | CNA | CVSS | 4.7 | MEDIUM | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N |
CVSS v4.0 Breakdown
CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:X/V:X/RE:M/U:X
CVSS v3.1 Breakdown
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Juniper Networks | Junos OS | affected 23.2R2-S1 23.2R2-S7 custom | MX Series |
| CNA | Juniper Networks | Junos OS | affected 23.4R2 23.4R2-S7 custom | MX Series |
| CNA | Juniper Networks | Junos OS | affected 24.2 24.2R2-S3 custom | MX Series |
| CNA | Juniper Networks | Junos OS | affected 24.4 24.4R2-S2 custom | MX Series |
| CNA | Juniper Networks | Junos OS | affected 25.2 25.2R2 custom | MX Series |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| supportportal.juniper.net/JSA110091 | [email protected] | supportportal.juniper.net | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Additional Advisory Data
Solutions
CNA: The following software releases have been updated to resolve this specific issue: Junos OS: 23.2R2-S7, 23.4R2-S7, 24.2R2-S3, 24.4R2-S2, 25.2R2, 25.4R1, and all subsequent releases.
Workarounds
CNA: There are no known workarounds for this issue.
Exploits
CNA: Juniper SIRT is not aware of any malicious exploitation of this vulnerability.