---
cve: "CVE-2026-11856"
severity: "CRITICAL"
cvss: 9.8
epss: "60%"
vendor: "curl"
kev: false
exploited: false
published: "2026-07-03 07:16:23"
tags: [cve, security, critical]
source: tsecurity.de CVE-Dossier
exported: "2026-09-14T11:13:11+02:00"
---

# CVE-2026-11856

> 9.8 CRITICAL

## Beschreibung

Successfully using libcurl to do a transfer to a specific HTTP origin
(`hostA`) with **Digest** authentication and then changing the origin to a
different one (`hostB`) for a second transfer, reusing the same handle, makes
libcurl wrongly pass on the  `Authorization:` header field meant for `hostA`,
to `hostB`.

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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 | Hoch | bad |
| I Integrität | Hoch | bad |
| A Verfügbarkeit | Hoch | bad |

## Patch verfügbar (OSV)

- 68720b4837284335b2d63cb358f8f6ce65f5bc55 (Commit)

## Referenzen

- <https://curl.se/docs/CVE-2026-11856.json>
- <https://curl.se/docs/CVE-2026-11856.html>
- <https://hackerone.com/reports/3793260>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-11856) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_