Cyber Resilience

CVE-2025-21593

Juniper Junos ≤ 21.2

Published
09 January 2025
Modified
26 January 2026
Patch / advisory
CVSS Score v4 7.1
Click a component to see what it means
Raw vectorCVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/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:X/R:A/V:X/RE:X/U:X
EPSS Score 0.0024 15th percentile
Risk Priority 35 floored blend · peak EPSS

Summary

CVE-2025-21593 is a high-severity Improper Control of a Resource Through its Lifetime (CWE-664) vulnerability in Juniper Junos. Its CVSS base score is 7.1 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Process Injection (T1055); 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-39 (Process Isolation) and SC-4 (Information in Shared System Resources) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

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…

more

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.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1055 Process Injection Stealth
Adversaries may inject code into processes in order to evade process-based defenses as well as possibly elevate privileges.
T1134 Access Token Manipulation Stealth
Adversaries may modify access tokens to operate under a different user or system security context to perform actions and bypass access controls.
T1134.002 Create Process with Token Stealth
Adversaries may create a new process with an existing token to escalate privileges and bypass access controls.
T1606 Forge Web Credentials Credential Access
Adversaries may forge credential materials that can be used to gain access to web applications or Internet services.
T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
T1134.001 Token Impersonation/Theft Stealth
Adversaries may duplicate then impersonate another user's existing token to escalate privileges and bypass access controls.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-36839Same product: Juniper Junos
CVE-2023-44184Same product: Juniper Junos
CVE-2024-39514Same product: Juniper Junos
CVE-2023-36849Same product: Juniper Junos
CVE-2024-30386Same product: Juniper Junos
CVE-2024-39564Same product: Juniper Junos
CVE-2024-30395Same product: Juniper Junos
CVE-2026-21921Same product: Juniper Junos
CVE-2025-30646Same product: Juniper Junos
CVE-2024-39543Same product: Juniper Junos

Affected Assets

juniper
junos
21.2, 21.4, 22.2, 22.3, 22.4 · ≤ 21.2
juniper
junos os evolved
21.2, 21.4, 22.2, 22.3, 22.4 · ≤ 21.2

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 4 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)

Mitigating Controls (NIST 800-53 r5) AI

SC-39 enforces separate execution domains so one process cannot corrupt or misuse another process's resources across their lifetimes.

SC-4 prevents unintended information transfer through shared resources, limiting blast radius when a product fails to release or reuse resources correctly.

SI-16 blocks unauthorized code execution in memory, stopping exploitation that commonly follows improper allocation, use-after-free, or deallocation errors.

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.

ID.AM-08 full match
prevents

Directly requires managing assets through creation, use, and disposal phases, preventing lifetime control failures.

PR.PS-01 mostly match
prevents

Enforces consistent configuration and handling rules that reduce improper resource lifetime management.

PR.PS-06 mostly match
prevents

Integrates secure practices across the full development lifecycle, addressing resource creation-to-release control.

PR.PS-02 partial match
prevents

Covers ongoing maintenance and removal of software, indirectly limiting resource lifetime issues.

PR.PS-03 partial match
prevents

Addresses hardware maintenance and replacement phases that intersect with resource lifetime control.

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.

prevents

Information deletion control ensures proper release and sanitization at end of life.

prevents

Secure SDLC embeds resource lifecycle controls from design through decommissioning.

prevents

Secure architecture principles reduce lifetime control issues but are not specific to them.

prevents

Secure coding practices help avoid lifetime control bugs but do not address the full scope.

degrades

Configuration management enforces lifecycle rules for resource creation, use and disposal.

none

Backups preserve resources but do not govern their full lifetime control.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Windows Server 2016 (2 rules)
  • V-224971 The Active Directory SYSVOL directory must have the proper access control permissions. prevents CWE-664
  • V-224970 Permissions on the Active Directory data files must only allow System and Administrators access. prevents CWE-664
Windows Server 2019 (1 rule)
  • V-205739 Windows Server 2019 permissions on the Active Directory data files must only allow System and Administrators access. prevents CWE-664

References