---
cve: "CVE-2026-43970"
severity: "HIGH"
cvss: 8.2
epss: "0.5%"
vendor: "ninenines"
kev: false
exploited: false
published: "2026-05-13 19:17:25"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-21T14:47:40+02:00"
---

# CVE-2026-43970

> 8.2 HIGH · 🧪 PoC

## Beschreibung

Improper Handling of Highly Compressed Data (Data Amplification) vulnerability in ninenines cowlib allows unauthenticated remote denial of service via memory exhaustion.

cow_spdy:inflate/2 in cowlib passes peer-supplied compressed bytes directly to zlib:inflate/2 with no output size bound. The SPDY header compression dictionary (?ZDICT) is public, and zlib compresses long runs of repeated bytes at roughly 1024:1, so a few kilobytes of SPDY frame payload can decompress to gigabytes on the BEAM heap, OOM-killing the node. A single unauthenticated SPDY frame is sufficient to trigger the condition. The parsers for syn_stream, syn_reply, and headers frame types are all affected via cow_spdy:parse_headers/2.

This issue affects cowlib from 0.1.0 before 2.16.1.

## CVSS-Vektor

```
CVSS:4.0/AV:N/AC:L/AT:P/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)
- 16aad3fb9f81f5cda4d1706ff0c54237c619c282 (Commit)

## Referenzen

- <https://cna.erlef.org/cves/CVE-2026-43970.html>
- <https://osv.dev/vulnerability/EEF-CVE-2026-43970>
- <https://github.com/ninenines/cowlib/commit/16aad3fb9f81f5cda4d1706ff0c54237c619c282>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-43970) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_