A stack-based buffer overflow (CWE-121) exists in the iked IKE key-management daemon of Juniper Networks Junos OS on SRX Series routers. The flaw is reached through the remote-access VPN authentication and JIMS identity-publishing path when a client is authenticated. When triggered, the overflow allows the attacker to execute arbitrary code with root privileges or to crash the VPN service, resulting in either a denial of service or root-level code execution.

The vulnerability affects Junos OS versions running on SRX Series devices. The fix has been incorporated into releases 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 releases. Respins are also available for earlier 23.2, 23.4, and 24.2 builds to provide the same protection.

The CVSS score is 8.7, categorising the issue as high severity. EPSS score is < 1% and the vulnerability is not listed in the CISA KEV catalog. Exploitation requires a valid authenticated VPN client account with the JIMS identity-publishing feature enabled. The attack vector is remote over the VPN service, so the risk is greatest for environments that expose remote-access VPNs and allow widely distributed credentials.