CVE-2026-57031
Last modified
CVE-2026-57031 is a medium-severity vulnerability rated 5.3/10 on the CVSS scale. 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.. EPSS estimates a 0.24% chance of exploitation in the next 30 days.
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.
Metrics
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
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
Weakness Enumeration
Affected Software
Source: CNA advisory (CVE.org). NVD analysis pending.
| Vendor | Product | Versions |
|---|---|---|
| Juniper Networks | Junos OS | >= 23.2R2-S1, < 23.2R2-S7; >= 23.4R2, < 23.4R2-S7; >= 24.2, < 24.2R2-S3; >= 24.4, < 24.4R2-S2; >= 25.2, < 25.2R2 |
References
Timeline
- Published
- Last Modified
- Status
- Awaiting Analysis
Frequently Asked Questions
What is CVE-2026-57031?
How severe is CVE-2026-57031?
How do I fix CVE-2026-57031?
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
Related CVEs from 2026
- CVE-2026-57025A Return of Pointer Value Outside of Expected Range vulnerab…6.8
- CVE-2026-57026An Improper Validation of Syntactic Correctness of Input vul…8.7
- CVE-2026-57027A Missing Release of Memory after Effective Lifetime vulnera…7.1
- CVE-2026-57028An Improper Restriction of Communication Channel to Intended…7.3
- CVE-2026-57029A Missing Synchronization vulnerability in the flow collecto…6
- CVE-2026-57030A Concurrent Execution using Shared Resource with Improper S…8.2
- CVE-2026-57032An Improper Handling of Undefined Parameters vulnerability i…7.1
- CVE-2026-5704A flaw was found in tar. A remote attacker could exploit thi…5.5
- CVE-2026-5705A vulnerability was identified in code-projects Online Hotel…4.3
- CVE-2026-57053GNU libidn before 1.44 is prone to out-of-bounds reads of un…2.5
- CVE-2026-57054A Use of Incorrectly-Resolved Name or Reference vulnerabilit…6.9
- CVE-2026-57062CMS (Cryptographic Message Syntax) parsing in gpgsm in GnuPG…2.9
Are you affected by CVE-2026-57031?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST