CVE-2026-12503: Loytec LINX firmware: Improper Link Resolution in /usr/bin/larm_starter

Severity: critical (CVSS 9.2 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-24 · updated 2026-07-27
Weakness: CWE-59

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`.

Affected products

Loytec L-DALI: through 8.4.16
Loytec L-GATE: through 8.4.16
Loytec L-INX: through 8.4.16
Loytec L-IOB: through 8.4.16
Loytec L-PAD: through 8.4.16
Loytec L-ROC: through 8.4.16
Loytec L-VIS: through 8.4.16
Loytec LIP-ME20xC: through 8.4.16

References

https://www.loytec.com/support/product-security/advisories/8520-dibt-cve-20260526-0002-symlink-following-in-chown-chmod-critical

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