This vulnerability (CWE-59) arises from improper handling of symbolic links in the larm_starter binary of Loytec L-INX and related products. An authenticated attacker with larmapp privileges can create a symlink pointing /etc/lighttpd/ssl/server.pem to /etc/passwd, causing the system to incorrectly grant write permissions to /etc/passwd for the larmapp group. This misconfiguration can be leveraged to escalate privileges to root. The issue affects versions through 8.4.16 on LINX-A64. No official patch or remediation level has been published yet.

Successful exploitation allows an authenticated attacker with larmapp group privileges to modify /etc/passwd, enabling root privilege escalation. This compromises system integrity and could lead to full system takeover. The CVSS 4.0 score is 9.2 (critical), reflecting high impact on confidentiality, integrity, and availability with low attack complexity but requiring high privileges.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, restrict access to the larmapp group and monitor for suspicious activity related to symlink creation or modification of /etc/lighttpd/ssl/server.pem. Avoid running untrusted code with larmapp privileges.