---
cve: "CVE-2026-73257"
severity: "CRITICAL"
cvss: 9.1
epss: "55.4%"
vendor: "Cesanta"
kev: false
exploited: false
published: "2026-08-20 18:16:46"
tags: [cve, security, critical]
source: tsecurity.de CVE-Dossier
exported: "2026-09-04T01:54:47+02:00"
---

# CVE-2026-73257

> 9.1 CRITICAL · 🧪 PoC

## Beschreibung

Mongoose is an embedded web server and network library. Priro to version 7.22, a remote unauthenticated attacker can send an HTTP request containing both Content-Length and Transfer-Encoding: chunked. The cl_count and te_count checks in the mg_http_parse() and http_cb() paths in src/http.c accept both headers and prioritize chunked encoding, while a Content-Length-preferring reverse proxy can use a different request boundary. This CL.TE desynchronization can inject requests that access or modify resources in another user context. This issue is fixed in version 7.22.

## CVSS-Vektor

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

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

## Patch verfügbar (OSV)

- a9df523f76f43a38bd53b4232b9cfd4c16869e71 (Commit)
- beb73a65a99619ff349c59037ea5197f27c7e533 (Commit)

## Referenzen

- <https://github.com/cesanta/mongoose/security/advisories/GHSA-5wfq-r6mr-wqp6>
- <https://github.com/cesanta/mongoose/pull/3611>
- <https://github.com/cesanta/mongoose/commit/a9df523f76f43a38bd53b4232b9cfd4c16869e71>
- <https://github.com/cesanta/mongoose/releases/tag/7.22>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-73257) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_