CVE-2026-57031
Junos OS: MX Series: For subscribers configured on static interfaces, input filters are not in effect
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.
INFO
Published Date :
July 9, 2026, 10:17 p.m.
Last Modified :
July 9, 2026, 10:17 p.m.
Remotely Exploit :
No
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-57031
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | 8cbe9d5a-a066-4c94-8978-4b15efeae968 | ||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 4.0 | MEDIUM | 8cbe9d5a-a066-4c94-8978-4b15efeae968 | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Update Junos OS to a fixed version.
- Verify firewall filter enforcement on static interfaces.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-57031.
| URL | Resource |
|---|---|
| https://supportportal.juniper.net/JSA110091 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-57031 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-57031
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-57031 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-57031 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Jul. 09, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'Juniper Networks', 'modules': ['MPC10', 'MPC11', 'LC4800', 'LC9600', 'MX304-LMIC16'], 'product': 'Junos OS', 'versions': [{'status': 'affected', 'version': '23.2R2-S1', 'lessThan': '23.2R2-S7', 'versionType': 'custom'}, {'status': 'affected', 'version': '23.4R2', 'lessThan': '23.4R2-S7', 'versionType': 'custom'}, {'status': 'affected', 'version': '24.2', 'lessThan': '24.2R2-S3', 'versionType': 'custom'}, {'status': 'affected', 'version': '24.4', 'lessThan': '24.4R2-S2', 'versionType': 'custom'}, {'status': 'affected', 'version': '25.2', 'lessThan': '25.2R2', 'versionType': 'custom'}], 'platforms': ['MX Series'], 'defaultStatus': 'unaffected'}] Added 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. Added CVSS V4.0 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 Added CVSS V3.1 AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N Added CWE CWE-754 Added Reference https://supportportal.juniper.net/JSA110091