---
cve: "CVE-2026-12503"
severity: "CRITICAL"
cvss: 9.2
epss: "14%"
vendor: "LOYTEC"
kev: false
exploited: false
published: "2026-07-24 15:17:10"
tags: [cve, security, critical]
source: tsecurity.de CVE-Dossier
exported: "2026-09-06T04:54:03+02:00"
---

# CVE-2026-12503

> 9.2 CRITICAL

## Beschreibung

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`.

## CVSS-Vektor

```
CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:H/SA:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Lokal | good |
| AC Komplexität | Gering | bad |
| PR Privilegien | Hoch | good |
| UI Interaktion | Keine | bad |

## Schwachstellen-Klasse

- **CWE-59** — Improper Link Resolution Before File Access ('Link Following')
  The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.

## Angriffsmuster (CAPEC)

- [CAPEC-17 — Using Malicious Files](https://capec.mitre.org/data/definitions/17.html) _(Severity: Very High)_
- [CAPEC-35 — Leverage Executable Code in Non-Executable Files](https://capec.mitre.org/data/definitions/35.html) _(Severity: Very High)_
- [CAPEC-76 — Manipulating Web Input to File System Calls](https://capec.mitre.org/data/definitions/76.html) _(Severity: Very High)_
- [CAPEC-132 — Symlink Attack](https://capec.mitre.org/data/definitions/132.html) _(Severity: High)_

## ATT&CK-Techniken

- [T1574.005 — Hijack Execution Flow: Executable Installer File Permissions](https://attack.mitre.org/techniques/T1574/005/)
- [T1574.010 — Hijack Execution Flow: Services File Permissions Weakness](https://attack.mitre.org/techniques/T1574/010/)
- [T1027.006 — Obfuscated Files or Information: HTML Smuggling](https://attack.mitre.org/techniques/T1027/006/)
- [T1027.009 — Obfuscated Files or Information: Embedded Payloads](https://attack.mitre.org/techniques/T1027/009/)
- [T1564.009 — Hide Artifacts: Resource Forking](https://attack.mitre.org/techniques/T1564/009/)
- [T1547.009 — Boot or Logon Autostart Execution:Shortcut Modification](https://attack.mitre.org/techniques/T1547/009/)

## Referenzen

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

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-12503) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_