---
cve: "CVE-2026-7790"
severity: "HIGH"
cvss: 8.7
epss: "0.4%"
vendor: "ninenines"
kev: false
exploited: false
published: "2026-05-11 19:16:29"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-24T12:31:05+02:00"
---

# CVE-2026-7790

> 8.7 HIGH · 🧪 PoC

## Beschreibung

Uncontrolled Resource Consumption vulnerability in ninenines cowlib (cow_http_te module) allows Excessive Allocation.

The chunked transfer-encoding parser in cow_http_te accepts an unbounded number of hex digits in the chunk-size field. Each digit causes a bignum multiplication (Len * 16 + digit), so parsing N hex digits requires O(N²) CPU work and O(N) memory. Additionally, when input is drip-fed, the parser discards the accumulated length on each partial read and restarts from zero on resumption, raising the cost to O(N³). An unauthenticated remote attacker can exploit this by sending an HTTP/1.1 request with Transfer-Encoding: chunked and a very long chunk-size hex string to cause denial of service through CPU exhaustion and memory amplification.

This vulnerability is associated with program file src/cow_http_te.erl and program routines cow_http_te:stream_chunked/2, cow_http_te:chunked_len/4.

This issue affects cowlib: from 0.6.0 before 2.16.1.

## CVSS-Vektor

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

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

## Patch verfügbar (OSV)

- bae6b022af54566f3518a3aa59083b4591d552de (Commit)
- a4b8039ce8c93ab00867ef6b7e888822c09f4369 (Commit)

## Referenzen

- <https://cna.erlef.org/cves/CVE-2026-7790.html>
- <https://osv.dev/vulnerability/EEF-CVE-2026-7790>
- <https://github.com/ninenines/cowlib/commit/a4b8039ce8c93ab00867ef6b7e888822c09f4369>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-7790) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_