CVE intelligence and bounded remediation

CVE-2024-39520 — Juniper Junos Os Evolved security vulnerability

High CVSS 8.5

An Improper Neutralization of Special Elements vulnerability in Juniper Networks Junos OS Evolved commands allows a local, authenticated attacker with low privileges to escalate their privileges to 'root' leading to a full compromise of the system. The Junos OS Evolved CLI doesn't properly handle command options in some cases, allowing users which execute specific CLI commands with a crafted set of parameters to escalate their privileges to root on shell level. This issue affects Junos OS Evolved: * All version before 20.4R3-S6-EVO, * 21.2-EVO versions before 21.2R3-S4-EVO, * 21.4-EVO versions before 21.4R3-S6-EVO, * 22.2-EVO versions before 22.2R2-S1-EVO, 22.2R3-EVO, * 22.3-EVO versions before 22.3R2-EVO.

Severity
High
CVSS
8.5 (4.0)
Published
2024-07-11
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-78

Affected products

  • juniper / junos_os_evolved
  • juniper / junos_os_evolved / 20.4

Showing 2 representative product identities from 48 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Command, code, expression, and template injection

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Trace untrusted values to process execution, interpreters, evaluators, template engines, dynamic imports, and administrative scripting features.
  • Determine whether the affected path is reachable across each trust boundary and which service account or host privilege it inherits.
  • Review configuration for optional execution features, unsafe compatibility modes, and shell invocation.

Remediate safely

  • Replace string-built commands or evaluated code with fixed operations and structured argument APIs that do not invoke a shell.
  • Use strict allowlists for operation identifiers and reject unexpected input before it reaches any interpreter.
  • Update the affected component and add inert regression tests covering metacharacters, encoding variants, and alternate request paths.

Authoritative sources

Complete CVE record and remediation plan

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