---
cve: "CVE-2026-27459"
severity: "HIGH"
cvss: 7.2
epss: "0.7%"
vendor: "pyca"
kev: false
exploited: false
published: "2026-03-17 23:34:28"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-21T10:43:43+02:00"
---

# CVE-2026-27459

> 7.2 HIGH · 🧪 PoC

## Beschreibung

pyOpenSSL is a Python wrapper around the OpenSSL library. Starting in version 22.0.0 and prior to version 26.0.0, if a user provided callback to `set_cookie_generate_callback` returned a cookie value greater than 256 bytes, pyOpenSSL would overflow an OpenSSL provided buffer. Starting in version 26.0.0, cookie values that are too long are now rejected.

## CVSS-Vektor

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

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

## Patch verfügbar (OSV)

- 358cbf29c4e364c59930e53a270116249581eaa3 (Commit)
- 57f09bb4bb051d3bc2a1abd36e9525313d5cd408 (Commit)

## Referenzen

- <https://github.com/pyca/pyopenssl/security/advisories/GHSA-5pwr-322w-8jr4>
- <https://github.com/pyca/pyopenssl/commit/57f09bb4bb051d3bc2a1abd36e9525313d5cd408>
- <https://github.com/pyca/pyopenssl/blob/358cbf29c4e364c59930e53a270116249581eaa3/CHANGELOG.rst>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-27459) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_