---
cve: "CVE-2026-55490"
severity: "MEDIUM"
cvss: 6.5
epss: "99%"
vendor: "OpenWRT"
kev: false
exploited: false
published: "2026-07-07 22:16:54"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-08T23:39:35+02:00"
---

# CVE-2026-55490

> 6.5 MEDIUM · 🧪 PoC

## Beschreibung

OpenWrt is a Linux operating system targeting embedded devices. Before v25.12.5, an integer underflow in handle_send_a() of the Emergency Access Daemon allows any unauthenticated attacker on the local network to crash the daemon by sending a single crafted UDP packet. The message length underflows before a bounds check and is then passed to memcpy as a very large size. This issue is fixed v25.12.5.

## CVSS-Vektor

```
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Benachbart | warn |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Keine | good |
| I Integrität | Keine | good |
| A Verfügbarkeit | Hoch | bad |

## Patch verfügbar (OSV)

- f0a60eee2fe051741c643ea6118718aae1ef17fb (Commit)

## Referenzen

- <https://github.com/openwrt/openwrt/security/advisories/GHSA-9558-77jp-g3fw>
- <https://github.com/openwrt/openwrt/commit/63c0767f3d02f7b10b0f0b5293366bd059a08ca5>
- <https://github.com/openwrt/openwrt/releases/tag/v25.12.5>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-55490) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_