Vulnerability · Published Jul 9, 2026 · Assigned by juniper
CVE-2026-57054Junos OS: MX Series: Web filtering doesn't block specifically formatted URLs
Medium 5.8
In plain English
A medium-severity security flaw in Junos OS from Juniper Networks. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 31% of all known vulnerabilities).
Official description
A Use of Incorrectly-Resolved Name or Reference vulnerability in the URL filtering plugin of Juniper Networks Junos OS on MX Series allows an unauthenticated, network-based attacker to bypass web filtering and access downstream resources that should be unreachable. If an MX Series device is configured with web filtering, and an attacker sends a request with a specifically formatted URL, this request will get forwarded despite the system being configured to block it. In turn, an attacker can access downstream resources that are expected to be unreachable. This issue affects Junos OS on MX Series: * all versions before 23.2R2-S7, * 23.4 versions before 23.4R2-S8, * 24.2 versions before 24.2R2-S5, * 24.4 versions before 24.4R2-S4, * 25.2 versions before 25.2R2-S1, * 25.4 versions before 25.4R1-S2, 25.4R2.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Juniper Networks | Junos OS | 0 – before 23.2R2-S723.4 – before 23.4R2-S824.2 – before 24.2R2-S524.4 – before 24.4R2-S425.2 – before 25.2R2-S125.4 – before 25.4R1-S2, 25.4R2 |
Weakness: CWE-706 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
References
- https://supportportal.juniper.net/JSA110093 vendor-advisory