---
cve: "CVE-2021-21240"
severity: "HIGH"
cvss: 7.5
epss: "3.6%"
vendor: "httplib2"
kev: false
exploited: false
published: "2021-02-08 20:15:12"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-14T03:27:32+02:00"
---

# CVE-2021-21240

> 7.5 HIGH · 🧪 PoC

## Beschreibung

httplib2 is a comprehensive HTTP client library for Python. In httplib2 before version 0.19.0, a malicious server which responds with long series of "\xa0" characters in the "www-authenticate" header may cause Denial of Service (CPU burn while parsing header) of the httplib2 client accessing said server. This is fixed in version 0.19.0 which contains a new implementation of auth headers parsing using the pyparsing library.

## CVSS-Vektor

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

| 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 | Keine | good |
| I Integrität | Keine | good |
| A Verfügbarkeit | Hoch | bad |

## Patch verfügbar (OSV)

- 81e80d00c2b3cb51de6019cfd28b793184d7699a (Commit)
- bd9ee252c8f099608019709e22c0d705e98d26bc (Commit)

## Referenzen

- <https://github.com/httplib2/httplib2/security/advisories/GHSA-93xj-8mrv-444m>
- <https://github.com/httplib2/httplib2/pull/182>
- <https://github.com/httplib2/httplib2/commit/bd9ee252c8f099608019709e22c0d705e98d26bc>
- <https://pypi.org/project/httplib2>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2021-21240) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_