Juniper Networks has rolled out major security updates, addressing over two dozen vulnerabilities across its flagship Junos OS, Junos OS Evolved, and the Junos Space management platform. The latest patches include critical fixes aimed at preventing denial-of-service (DoS) attacks, data breaches, and potential device compromise.
The newly released updates fix 11 high-severity flaws in Junos OS, some of which also affect Junos OS Evolved. These bugs span several components, including the packet forwarding engine (pfe), flow daemon (flowd), routing protocol daemon (rpd), Anti-Virus processing modules, the jdhcpd daemon, syslog TCP stream transport, and web-based management interfaces. Some vulnerabilities are device-specific, impacting only certain models like the EX Series, MX Series, or SRX Series.
Most of these high-risk vulnerabilities could allow attackers to trigger a DoS condition, effectively knocking affected devices offline. However, Juniper has assured users that security patches are now available for all impacted platforms.
Alongside these, 10 medium-severity vulnerabilities have also been patched. While most of them also pose DoS risks, at least one allows an authenticated local user to extract sensitive information through the command-line interface—raising serious concerns for organizations with multi-user administrative environments.
In addition to the core OS updates, Juniper released Junos Space version 24.1R3, which addresses nearly 50 vulnerabilities tied to third-party components. Some of these issues have been labeled as critical, further highlighting the urgency for users to upgrade. Junos Space Security Director version 24.1R3 and CTP View version 9.2R1 have also received updates for third-party dependency flaws.
While there’s no confirmation of widespread exploitation, Juniper’s security team (SIRT) has issued warnings in at least one case. The company updated its advisory for CVE-2025-21590, a critical kernel vulnerability related to improper isolation. If exploited, this flaw could allow shell-level attackers to run arbitrary code and take full control of the affected system.
According to Juniper, patches for CVE-2025-21590 have already been issued for many products, though some models will only receive the fix in upcoming firmware versions. Notably, Juniper acknowledged reports of malicious exploitation targeting this specific vulnerability and has urged customers to apply available fixes immediately or implement mitigation strategies in the meantime.
