CVE-2026-57031
published 2026-07-09CVE-2026-57031: An Improper Check for Unusual or Exceptional Conditions vulnerability in the packet forwarding engine (PFE) of Juniper Networks Junos OS on MX Series allows…
PriorityP424medium4.7CVSS 3.1
AVAACLPRNUINSCCNILAN
EPSS
0.24%
14.8th percentile
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.
Affected
5 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| juniper_networks | junos_os | >= 23.2R2-S1 < 23.2R2-S7 | 23.2R2-S7 |
| juniper_networks | junos_os | >= 23.4R2 < 23.4R2-S7 | 23.4R2-S7 |
| juniper_networks | junos_os | >= 24.2 < 24.2R2-S3 | 24.2R2-S3 |
| juniper_networks | junos_os | >= 24.4 < 24.4R2-S2 | 24.4R2-S2 |
| juniper_networks | junos_os | >= 25.2 < 25.2R2 | 25.2R2 |
CVSS provenance
nvdv3.14.7MEDIUMCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
nvdv4.05.3MEDIUMCVSS: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
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VulDB
Juniper Junos OS up to 25.2R1 Packet Forwarding Engine error condition
vuldb·2026-07-10·CVSS 4.7
CVE-2026-57031 [MEDIUM] Juniper Junos OS up to 25.2R1 Packet Forwarding Engine error condition
A vulnerability was found in Juniper Junos OS up to 23.2R2-S6/23.4R2-S6/24.2R2-S2/24.4R2-S1/25.2R1. It has been classified as very critical. This vulnerability affects unknown code of the component Packet Forwarding Engine. This manipulation causes detection of error condition without action.
This vulnerability is tracked as CVE-2026-57031. The attack is possible to be carried out remotely. No exploit exists.
GHSA
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 f
ghsa_unreviewed·2026-07-10
CVE-2026-57031 [MEDIUM] CWE-754 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 f
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.
No detection rules found.
No public exploits indexed.
No writeups or analysis indexed.
2026-07-09
Published