CVE-2025-21590
MEDIUMCISA KEVEPSS 77th pctlDescription
An Improper Isolation or Compartmentalization vulnerability in the kernel of Juniper Networks Junos OS allows a local attacker with high privileges to compromise the integrity of the device. A local attacker with access to the shell is able to inject arbitrary code which can compromise an affected device. This issue is not exploitable from the Junos CLI. This issue affects Junos OS: * All versions before 21.2R3-S9, * 21.4 versions before 21.4R3-S10, * 22.2 versions before 22.2R3-S6, * 22.4 versions before 22.4R3-S6, * 23.2 versions before 23.2R2-S3, * 23.4 versions before 23.4R2-S4, * 24.2 versions before 24.2R1-S2, 24.2R2.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N
Exploit Intelligence
Elevated risk: more likely to be exploited than 77% of all known CVEs.
Juniper Junos OS Improper Isolation or Compartmentalization Vulnerability
Juniper Junos OS contains an improper isolation or compartmentalization vulnerability. This vulnerability could allows a local attacker with high privileges to inject arbitrary code.
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Remediation due: 2025-04-03
References
Related Vulnerabilities
Other CWE-653 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2025-1974 | Critical | 9.8 | 99% | - | - |
| CVE-2025-57738 | High | 7.2 | 23% | - | Fix |
| CVE-2026-24781 | Critical | 9.8 | 1.2% | - | Fix |
| CVE-2026-53421 | Critical | 9.8 | 1.1% | - | Fix |
| CVE-2024-0135 | High | 7.6 | 1.1% | - | Fix |
| CVE-2026-26956 | Critical | 9.8 | 0.9% | - | Fix |
Common questions
How do I fix CVE-2025-21590?
Upgrade junos to 21.2 or later.
Is CVE-2025-21590 being actively exploited?
Yes. CVE-2025-21590 is listed in the CISA Known Exploited Vulnerabilities catalog, which means exploitation has been observed in the wild. US federal agencies were required to remediate it by 2025-04-03. Treat it as a priority whatever its CVSS score says.
How severe is CVE-2025-21590?
CVE-2025-21590 has a CVSS v3 base score of 4.4, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2025-21590 affect?
Published advisories record a fix for junos (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
Embed a live status badge for CVE-2025-21590
Markdown
[](https://tridentstack.com/cve/CVE-2025-21590)HTML
<a href="https://tridentstack.com/cve/CVE-2025-21590"><img src="https://tridentstack.com/cve/badge/CVE-2025-21590.svg" alt="CVE-2025-21590"></a>This vulnerability is actively exploited in the wild
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-10-01.