---
cve: "CVE-2021-33033"
severity: "HIGH"
cvss: 7.8
epss: "21.5%"
vendor: "Linux"
kev: false
exploited: false
published: "2021-05-14 23:15:09"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-12T03:21:39+02:00"
---

# CVE-2021-33033

> 7.8 HIGH

## Beschreibung

The Linux kernel before 5.11.14 has a use-after-free in cipso_v4_genopt in net/ipv4/cipso_ipv4.c because the CIPSO and CALIPSO refcounting for the DOI definitions is mishandled, aka CID-ad5d07f4a9cd. This leads to writing an arbitrary value.

## CVSS-Vektor

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

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

## Referenzen

- <https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.11.14>
- <https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.11.7>
- <https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1165affd484889d4986cf3b724318935a0b120d8>
- <https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ad5d07f4a9cd671233ae20983848874731102c08>
- <https://sites.google.com/view/syzscope/kasan-use-after-free-read-in-cipso_v4_genopt>
- <https://syzkaller.appspot.com/bug?id=96e7d345748d8814901c91cd92084ed04b46701e>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2021-33033) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_