CVE-2026-9547
High
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.
SeverityHigh
CVSS7.4
Exploit probability—
ProductHaxx Curl
PublishedJul 3, 2026
First seenJul 3, 2026
Weakness typeCWE-297CWE-297
How to fix
Update
- haxx curl8.21.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| haxx curl | 7.69.0 ≤ v < 8.21.0 | 8.21.0 |
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