---
cve: "CVE-2026-33630"
severity: "HIGH"
cvss: 7.5
epss: "45%"
vendor: "c-ares"
kev: false
exploited: false
published: "2026-09-03 19:17:27"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-19T10:30:01+02:00"
---

# CVE-2026-33630

> 7.5 HIGH · 🧪 PoC

## Beschreibung

c-ares is an asynchronous resolver library. From ver 1.32.3 until 1.34.7, a use-after-free / double-free in c-ares' query-completion handling. The same flaw — a query's callback being invoked while the query is still linked in the channel's internal lookup structures — is present at multiple points in the resend/finish path (timeout handling, response handling, and query dispatch). If the query, or for ares_getaddrinfo() the owning host_query, is freed as a side effect of that callback, it is then accessed and/or freed a second time. This vulnerability is fixed in ver 1.34.7.

## 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)

- 1fa3b86a0b8d18fe7b60f3228a01d770feb026bc (Commit)
- d823199b688052dcdc1646f2ab4cb8c16b1c644a (Commit)

## Referenzen

- <https://github.com/c-ares/c-ares/security/advisories/GHSA-6wfj-rwm7-3542>
- <https://github.com/c-ares/c-ares/pull/1237>
- <https://github.com/c-ares/c-ares/commit/1fa3b86a0b8d18fe7b60f3228a01d770feb026bc>
- <https://github.com/c-ares/c-ares/commit/d823199b688052dcdc1646f2ab4cb8c16b1c644a>
- <https://github.com/c-ares/c-ares/releases/tag/v1.34.7>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-33630) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_