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.
CVSS Details
- CVSS 3.1 Base Score: 7.4
- CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alpine Linux | — | Upgrade curl | Jul 6, 2026 | Jul 3, 2026 |
| Ibm Aix | — | Apply the fix or workaround for curl_advisory11 | Jul 28, 2026 | Jul 28, 2026 |
| Redhat Openshift | — | Upgrade rhcos | Sep 3, 2026 | Jul 3, 2026 |
| Redhat_linux | — | Upgrade libcurl-minimalUpgrade curl-minimalUpgrade libcurl-minimal-debuginfoUpgrade curl-debuginfoUpgrade libcurlUpgrade curl-minimal-debuginfoUpgrade curl-debugsourceUpgrade libcurl-debuginfoUpgrade libcurl-develUpgrade curl | Jul 17, 2026 | Jul 3, 2026 |
| Rocky_linux | — | Upgrade curl-minimalUpgrade curlUpgrade libcurl-debuginfoUpgrade libcurl-develUpgrade libcurlUpgrade curl-debugsourceUpgrade curl-minimal-debuginfoUpgrade libcurl-minimal-debuginfoUpgrade libcurl-minimalUpgrade curl-debuginfo | Aug 20, 2026 | Aug 17, 2026 |
| Ubuntu | — | Upgrade libcurl4Upgrade libcurl4-nss-devUpgrade libcurl4 (Ubuntu Pro)Upgrade libcurl4-gnutls-dev (Ubuntu Pro)Upgrade libcurl4-openssl-dev (Ubuntu Pro)Upgrade libcurl4-gnutls-devUpgrade libcurl3-nssUpgrade libcurl3-gnutlsUpgrade libcurl3-gnutls (Ubuntu Pro)Upgrade libcurl4t64Upgrade libcurl4-openssl-devUpgrade libcurl4-nss-dev (Ubuntu Pro)Upgrade libcurl3t64-gnutlsUpgrade libcurl3-nss (Ubuntu Pro)Upgrade curlUpgrade libcurl3 (Ubuntu Pro)Upgrade curl (Ubuntu Pro) | Jul 1, 2026 | Jun 30, 2026 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | Aug 10, 2026 | Jul 3, 2026 |
Prioritise with Active Threat Intelligence
With curated Threat Intelligence, you can see which vulnerabilities truly put you at risk, prioritize what matters most, and act before attackers do.
Explore Intelligence Hub