CVE-2026-9547 | When a libcurl-based application performs transfers via `SCP…

Description

When a libcurl-based application performs transfers via `SCP://` or `SFTP://` and utilizes the `CURLOPT_SSH_KEYFUNCTION` callback, it may silently accept an untrusted server. This vulnerability occurs when a server presents a host key type that does not match the specific key type already recorded for that host in the `known_hosts` file. Instead of rejecting the mismatch, the callback mechanism fails to properly enforce the restriction, allowing the connection to succeed without warning and risking a potential man-in-the-middle attack.

Metadata

CVE ID: CVE-2026-9547
State: PUBLISHED
Assigner: curl
Reserved: 2026-05-26 06:45 UTC
Published: 2026-07-03 06:18 UTC
Last updated: 2026-07-03 06:18 UTC
Vendor / Product: curl / curl
Sources: cve.org · NVD

Severity & Metrics

No CVSS data available.

Affected products (1)

Vendor	Product	Platform	Versions
curl	curl	—	8.20.0 ≤ 8.20.0, 8.19.0 ≤ 8.19.0, 8.18.0 ≤ 8.18.0, 8.17.0 ≤ 8.17.0 …

Weakness (CWE)

CWE	Source	Description
—	cna	CWE-297 Improper Validation of Certificate with Host Mismatch

References (3)