CVE intelligence and bounded remediation

CVE-2025-21593 — Juniper Junos security vulnerability

High CVSS 7.1

An Improper Control of a Resource Through its Lifetime vulnerability in the routing protocol daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated network-based attacker to cause a Denial-of-Service (DoS). On devices with SRv6 (Segment Routing over IPv6) enabled, an attacker can send a malformed BGP UPDATE packet which will cause the rpd to crash and restart. Continued receipt of these UPDATE packets will cause a sustained DoS condition. This issue affects iBGP and eBGP, and both IPv4 and IPv6 are affected by this vulnerability.This issue affects Junos OS: * All versions before 21.2R3-S9, * from 21.4 before 21.4R3-S10, * from 22.2 before 22.2R3-S5, * from 22.3 before 22.3R3-S4, * from 22.4 before 22.4R3-S3, * from 23.2 before 23.2R2-S2, * from 23.4 before 23.4R2; and Junos OS Evolved: * All versions before 21.2R3-S9-EVO, * from 21.4-EVO before 21.4R3-S10-EVO, * from 22.2-EVO before 22.2R3-S5-EVO, * from 22.3-EVO before 22.3R3-S4-EVO, * from 22.4-EVO before 22.4R3-S3-EVO, * from 23.2-EVO before 23.2R2-S2-EVO, * from 23.4-EVO before 23.4R2-EVO.

Severity
High
CVSS
7.1 (4.0)
Published
2025-01-09
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-664

Affected products

  • juniper / junos
  • juniper / junos / 21.2

Showing 2 representative product identities from 154 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Race condition, TOCTOU, and lifecycle synchronization

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Check exposure

  • Map concurrent actors, shared state, lock boundaries, signals, callbacks, retries, and check-then-use sequences in the affected path.
  • Determine whether untrusted users can influence timing, object names, filesystem state, or repeated state transitions.
  • Identify clustered and multi-process behavior that repository-local tests may not represent.

Remediate safely

  • Make the sensitive state transition atomic or protect it with a consistently ordered synchronization primitive.
  • Perform authorization and invariant checks on the same authoritative object and transaction used for the operation.
  • Use unique private resources, safe ownership transfer, and idempotent operations; add deterministic concurrency regression tests.

Authoritative sources

Complete CVE record and remediation plan

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