CVE-2026-12503 Loytec LINX firmware: Improper Link Resolution in /usr/bin/larm_starter
An authenticated attacker can escalate privileges to root via a symlink attack in the larm_starter binary on Loytec LINX devices.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-12503?
CVE-2026-12503 is a critical path traversal vulnerability in Loytec L-DALI, published on 24 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
Improper Link Resolution (CWE-59) in `/usr/bin/larm_starter` in Loytec L-INX, L-GATE, L-ROC, L-IOB, L-DALI, L-VIS and L-PAD through 8.4.16 on LINX-A64 allows an authenticated `larmapp` attacker to make `/etc/passwd` writable by the `larmapp` group (leading to root privilege escalation) via a symlink attack on `/etc/lighttpd/ssl/server.pem`.
Weakness: CWE-59
Which versions are affected by CVE-2026-12503?
How do I fix CVE-2026-12503?
No fix has been published for CVE-2026-12503 yet. Limit exposure of the affected software until one is available.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-12503 being exploited?
There is no known exploitation of CVE-2026-12503 in the wild and no public exploit code.
Sources
Also known as GHSA-4p7f-6rpf-28mq.