Skip to content
USN-8227-1: curl vulnerabilities

USN-8227-1: curl vulnerabilities

Ubuntu May 4, 2026

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...

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 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 )

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 )

In general, a standard system update will make all the necessary changes.

The problem can be corrected by updating your system to the following package versions:

Ubuntu Pro provides ten-year security coverage to 25,000+ packages in Main and Universe repositories, and it is free for up to five machines.