The vulnerability is an OS command injection in the TACACS+ component of Juniper Networks Junos OS Evolved. A low‑privileged TACACS+ user can supply crafted input that is passed directly to the operating‑system shell during a periodic authorization‑refresh, allowing the attacker to execute arbitrary commands with root privileges, effectively gaining full process‑level control of the device.

All Juniper Networks Junos OS Evolved devices running the releases listed in the advisory – 23.2R2‑S7.7‑EVO, 23.4R2‑S8.11‑EVO, 24.2R2‑S5.6‑EVO, 24.4R2‑S5‑EVO, 25.2R2‑S2‑EVO, 25.2X100‑D35‑EVO, 25.4R1‑S3‑EVO, 25.4R2‑EVO, 25.4X300‑D40‑EVO, 26.2R1‑S2‑EVO, 26.2R2‑EVO, 26.4R1‑EVO and all subsequent releases.

The CVSS score of 9.3 indicates a high‑severity flaw. EPSS score of 2% indicates a low but non‑zero probability of exploitation in the wild, and the vulnerability is not listed in the CISA KEV catalog. The likely attack vector is network‑based; it requires a valid TACACS+ user account and relies on the periodic authorization‑refresh feature, so exploitation does not need additional conditions beyond legitimate authentication.