The curl packages in Red Hat Enterprise Linux 9 contain four distinct security vulnerabilities: CVE-2026-1965 involves an authentication bypass due to incorrect connection reuse with Negotiate authentication; CVE-2026-3783 allows information disclosure through OAuth2 bearer token leakage during HTTP(S) redirects; CVE-2026-9547 enables man-in-the-middle attacks by bypassing SSH host key verification; and CVE-2026-8286 causes insecure connection establishment due to TLS configuration mismatches. Red Hat has released updated packages to fix these vulnerabilities as detailed in advisory RHSA-2026:55439.

These vulnerabilities collectively impact the security of authentication mechanisms, confidentiality of OAuth2 tokens, integrity of SSH connections, and the security of TLS connections when using curl. Exploitation could lead to unauthorized access, token leakage, man-in-the-middle attacks, and insecure communications. The advisory rates the overall impact as Important (high severity). There are no known exploits in the wild at this time.

Red Hat has released updated curl packages for Red Hat Enterprise Linux 9 to address these vulnerabilities. Users should apply the security update as described in Red Hat advisory RHSA-2026:55439 and the referenced article https://access.redhat.com/articles/11258. Applying these updates will remediate the issues. No additional mitigation steps are indicated by the vendor.