CVE-2026-57032
Juniper Junos ≤ 23.2
Raw vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/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:A/V:X/RE:M/U:XSummary
CVE-2026-57032 is a high-severity Improper Handling of Undefined Parameters (CWE-236) vulnerability in Juniper Junos. Its CVSS base score is 7.1 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Application or System Exploitation (T1499.004); ranked at the 15th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SC-7 (Boundary Protection) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-42723
Vulnerability Data
An Improper Handling of Undefined Parameters vulnerability in the packet forwarding engine (pfe) of Juniper Networks Junos OS on EX Series devices allows an authenticated attacker with low privileges to cause a Denial-of-Service (DoS). If an attempt is made to…
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subscribe to an unsupported telemetry sensor path on EX2300, EX3400, EX4000, EX4100 and EX4400 via gRPC, this causes the FPC to crash. This leads to a complete service outage until the module has automatically restarted. The following log message can be seen when this issue happens: agentd[<PID>]: AGENTD_RESOURCE_NOT_FOUND: No resource name found for <sensor> This issue affects Junos OS on EX2300, EX3400, EX4000, EX4100 and EX4400 devices: * 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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
The vulnerability allows an authenticated low-privileged attacker to crash the FPC via an unsupported gRPC telemetry sensor path, resulting in a complete service outage (DoS) on affected Juniper EX switches. This directly maps to T1499.004 (Endpoint Denial of Service: Application or System Exploitation).
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
Mitigating Controls (NIST 800-53 r5) AI
Boundary protection at the gRPC telemetry interface can block or restrict subscription requests for unsupported sensor paths before they reach the packet forwarding engine.
Input validation of telemetry sensor paths prevents malformed or unsupported subscriptions from being processed by the FPC, avoiding the crash.
Timely application of the vendor-supplied patches (23.2R2-S7, 23.4R2-S8, etc.) eliminates the improper handling of undefined parameters in the PFE.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly require robust input validation and parameter handling to prevent this weakness.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing can detect undefined-parameter handling flaws but does not prevent them at the source.
Secure development lifecycle requires explicit definition and validation of all parameters, reducing undefined-parameter handling issues.
Application security requirements mandate complete parameter specifications and error handling for unsupported inputs.
Secure coding standards directly address proper handling of undefined or unsupported parameters during implementation.