The vulnerability is an improper input validation flaw in the rpd process of Juniper Networks Junos OS and Junos OS Evolved. An unauthenticated adjacent attacker can send a malformed PIM Hello message on an IPv6‑enabled PIM interface, causing rpd to crash. The crash leads to a denial of service because rpd is responsible for routing and reaching network neighbors. The weakness aligns with CWE‑20 (Improper Input Validation).

Affected products are Juniper Networks Junos OS and Junos OS Evolved. Firmware releases that include the fix are 23.2R2‑S7.7, 23.4R2‑S8.13, 24.2R2‑S5.5, 24.4R2‑S5, 25.2R2‑S2, 25.4R1‑S3, 25.4R2, 26.2R1‑S2, 26.2R2, 26.4R1 and all subsequent Junos OS releases; and 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 Junos OS Evolved releases.

The CVSS score of 7.1 signals a moderate severity vulnerability. Because the attack requires an unauthenticated attacker who is adjacent to the router and only needs to send a malformed PIM Hello packet on an IPv6‑enabled PIM interface, the exploit is straightforward for a local attacker. The EPSS score is not available and the vulnerability is not listed in the CISA KEV catalog, indicating that while the probability of public exploitation may not yet be high, the presence of an obvious local route to impact makes this a reasonable concern for on‑premises deployments.