CVE intelligence and bounded remediation

CVE-2025-21602 — Juniper Junos security vulnerability

High CVSS 7.1

An Improper Handling of Exceptional Conditions vulnerability in the routing protocol daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated adjacent attacker sending a specific BGP update packet to cause rpd to crash and restart, resulting in a Denial of Service (DoS). Continuous receipt and processing of this packet will create a sustained Denial of Service (DoS) condition. This issue affects iBGP and eBGP, and both IPv4 and IPv6 are affected by this vulnerability. This issue affects Junos OS: * from 21.4 before 21.4R3-S9, * from 22.2 before 22.2R3-S5, * from 22.3 before 22.3R3-S4, * from 22.4 before 22.4R3-S5, * from 23.2 before 23.2R2-S3, * from 23.4 before 23.4R2-S3, * from 24.2 before 24.2R1-S2, 24.2R2; This issue does not affect versions prior to 21.1R1. Junos OS Evolved: * from 21.4 before 21.4R3-S9-EVO, * from 22.2 before 22.2R3-S5-EVO, * from 22.3 before 22.3R3-S4-EVO, * from 22.4 before 22.4R3-S5-EVO, * from 23.2 before 23.2R2-S3-EVO, * from 23.4 before 23.4R2-S3-EVO, * from 24.2 before 24.2R1-S2-EVO, 24.2R2-EVO. This issue does not affect versions prior to 21.1R1-EVO

Severity
High
CVSS
7.1 (4.0)
Published
2025-01-09
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-755

Affected products

  • juniper / junos / 21.2

Showing 1 representative product identities from 169 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Resource exhaustion and denial of service

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

Check exposure

  • Identify attacker-influenced work factors including input size, nesting, compression, fan-out, regex cost, allocation, recursion, retries, and connection lifetime.
  • Map per-request and shared CPU, memory, disk, descriptor, thread, queue, and downstream-service limits.
  • Determine whether authentication, tenancy, quotas, and rate controls apply before expensive processing begins.

Remediate safely

  • Bound input size, nesting, expansion, work, concurrency, queue depth, retries, and execution time before resource-intensive processing.
  • Release resources on every success, error, cancellation, and timeout path and use backpressure instead of unbounded buffering.
  • Update affected components and add small deterministic tests that assert resource ceilings rather than exhausting a host.

Authoritative sources

Complete CVE record and remediation plan

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