Multiple vulnerabilities impacts AIX due to cURL libcurl (CVE-2025-14819 CVE-2026-1965 CVE-2026-3783 CVE-2026-3784 CVE-2026-5545)

IBM SECURITY ADVISORY First Issued: Fri Jun 26 01:16:13 CDT 2026 The most recent version of this document is available here: https://aix.software.ibm.com/aix/efixes/security/curladvisory10.asc Security Bulletin: Multiple vulnerabilities impacts AIX due to cURL libcurl CVE-2025-14819, CVE-2026-196...

libcurl 7.43.0 < 8.21.0 Wrong Negotiate Connection Reuse

The version of libcurl installed on the remote host is 7.43.0 prior to 8.21.0. It is, therefore, affected by an improper connection reuse vulnerability: - libcurl might in some circumstances reuse the wrong connection when asked to do Negotiate-authenticated ones, even when they are set to use...

libcurl 7.7 < 8.21.0 Incomplete mTLS Config Matching in Connection Reuse

The version of libcurl installed on the remote host is 7.7 prior to 8.21.0. It is, therefore, affected by an improper certificate validation vulnerability: - libcurl would reuse a previously created connection even when some mTLS config related option had been changed that should have prohibited...

UBUNTU-CVE-2026-8458

libcurl might in some circumstances reuse the wrong connection when asked to do Negotiate-authenticated ones, even when they are set to use different "services". libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection to avoid overhead. When...

CVE-2026-11564

libcurl keeps previously used connections in a connection pool for subsequent transfers to reuse if one of them matches the setup. An easy handle that first uses default native CA trust can continue trusting the native platform store after the application switches that same handle to custom CA...

CVE-2026-8932

libcurl would reuse a previously created connection even when some mTLS config related option had been changed that should have prohibited reuse. libcurl keeps previously used connections in a connection pool for subsequent transfers to reuse if one of them matches the setup. However, some TLS...

CVE-2026-8458

libcurl might in some circumstances reuse the wrong connection when asked to do Negotiate-authenticated ones, even when they are set to use different "services". libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection to avoid overhead. When...

UBUNTU-CVE-2026-8932

libcurl would reuse a previously created connection even when some mTLS config related option had been changed that should have prohibited reuse. libcurl keeps previously used connections in a connection pool for subsequent transfers to reuse if one of them matches the setup. However, some TLS...

curl: curl: Insecure connection establishment due to TLS configuration mismatch

A flaw was found in curl. When a new data transfer attempts to upgrade its connection using STARTTLS, it may incorrectly reuse an existing live connection. This reuse can occur even if the Transport Layer Security TLS configuration of the new transfer does not match the existing connection,...

libcurl: libcurl: Security feature bypass due to improper mTLS connection reuse

A flaw was found in curl. The libcurl library, used for transferring data with URLs, could improperly reuse existing network connections. This occurred even when changes to mutual Transport Layer Security mTLS settings, particularly those for client certificates, should have prevented such reuse...

libcurl: libcurl: Certificate validation bypass due to incorrect connection reuse

A flaw was found in curl. When libcurl reuses a connection from its connection pool, an easy handle that initially used default native Certificate Authority CA trust may continue to trust the native platform store. This occurs even after the application has switched that same handle to custom CA...

CURL-CVE-2026-11564 Native CA trust persist

libcurl keeps previously used connections in a connection pool for subsequent transfers to reuse if one of them matches the setup. An easy handle that first uses default native CA trust can continue trusting the native platform store after the application switches that same handle to custom CA...

CURL-CVE-2026-8286 wrong STARTTLS connection reuse

A vulnerability exists where a new transfer that uses STARTTLS to upgrade the connection might reuse an existing live connection even though the TLS configuration mismatches so it should not...

CURL-CVE-2026-8458 wrong reuse for different services

libcurl might in some circumstances reuse the wrong connection when asked to do Negotiate-authenticated ones, even when they are set to use different "services". libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection to avoid overhead. When...

wrong STARTTLS connection reuse

A vulnerability exists where a new transfer that uses STARTTLS to upgrade the connection might reuse an existing live connection even though the TLS configuration mismatches so it should not...

incomplete mTLS config matching in conn reuse

libcurl would reuse a previously created connection even when some mTLS config related option had been changed that should have prohibited reuse. libcurl keeps previously used connections in a connection pool for subsequent transfers to reuse if one of them matches the setup. However, some TLS...

wrong reuse for different services

libcurl might in some circumstances reuse the wrong connection when asked to do Negotiate-authenticated ones, even when they are set to use different "services". libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection to avoid overhead. When...

CURL-CVE-2026-8932 incomplete mTLS config matching in conn reuse

libcurl would reuse a previously created connection even when some mTLS config related option had been changed that should have prohibited reuse. libcurl keeps previously used connections in a connection pool for subsequent transfers to reuse if one of them matches the setup. However, some TLS...

PT-2026-51751

Name of the Vulnerable Software and Affected Versions libcurl versions 7.7 through 8.20.x Description libcurl incorrectly reuses previously created connections from its connection pool even when mutual TLS mTLS configuration options have changed. The connection-reuse check fails to validate five...

PT-2026-51746

Name of the Vulnerable Software and Affected Versions libcurl affected versions not specified Description A logical error in the connection pooling mechanism allows the software to reuse an incorrect connection for Negotiate-authenticated requests. This occurs even when the requests are configure...