---
cve: "CVE-2026-66032"
severity: "HIGH"
cvss: 8.7
epss: "28%"
vendor: "libssh2"
kev: false
exploited: false
published: "2026-07-24 17:17:35"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-04T00:35:16+02:00"
---

# CVE-2026-66032

> 8.7 HIGH · 🧪 PoC

## Beschreibung

libssh2 through 1.11.1, fixed in commit 5e47761, contains a double-free vulnerability in the sftp_open() function in src/sftp.c that allows a malicious SSH server to corrupt the heap of any authenticated client opening an SFTP session. When a server responds to SSH_FXP_OPEN with SSH_FXP_STATUS containing FX_OK, the response data buffer is freed, and if a subsequent sftp_packet_require() call returns a specific error such as LIBSSH2_ERROR_CHANNEL_PACKET_EXCEEDED, the same pointer is freed a second time, enabling tcache dup conditions on glibc systems that allow overlapping allocations and function pointer overwrites.

## CVSS-Vektor

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

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |

## Patch verfügbar (OSV)

- 5e4776146552d898b9c0e1b313cd093fa8dc92d0 (Commit)

## Referenzen

- <https://github.com/libssh2/libssh2/pull/2180>
- <https://github.com/libssh2/libssh2/commit/5e4776146552d898b9c0e1b313cd093fa8dc92d0>
- <https://www.vulncheck.com/advisories/libssh2-double-free-heap-corruption-via-sftp-open>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-66032) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_