curl vulnerabilities

Summary

It was discovered that curl incorrectly reused non-TLS connections when TLS was required in some STARTTLS configurations. A remote attacker could possibly use this issue to obtain sensitive information. (CVE-2026-4873) It was discovered that curl incorrectly reused certain HTTP Negotiate connections. A remote attacker could possibly use this issue to obtain sensitive information. (CVE-2026-5545) It was discovered that curl incorrectly reused certain SMB connections. A remote attacker could possibly use this issue to obtain sensitive information. (CVE-2026-5773) It was discovered that curl could leak proxy credentials when handling redirects in some configurations. A remote attacker could possibly use this issue to obtain sensitive information. (CVE-2026-6253) It was discovered that curl could leak cookies because of stale custom cookie host handling in some requests. A remote attacker could possibly use this issue to obtain sensitive information. (CVE-2026-6276) It was discovered that curl could leak .netrc credentials when reusing proxy connections in some situations. A remote attacker could possibly use this issue to obtain sensitive information. (CVE-2026-6429) It was discovered that curl could leak Digest authentication state when switching proxies in some situations. A remote attacker could possibly use this issue to obtain sensitive information. (CVE-2026-7168) Affected Ubuntu releases: 26.04, 25.10, 24.04, 22.04. CVEs: CVE-2026-4873, CVE-2026-5773, CVE-2026-5545, CVE-2026-6429, CVE-2026-6276, CVE-2026-6253, CVE-2026-7168.