libcurl 7.71.0 < 8.20.0 Cookie Leak via Stale Host Header

The version of libcurl installed on the remote host is 7.71.0 prior to 8.20.0. It is, therefore, affected by a cookie leak vulnerability: - When using the same connection handle for multiple HTTP requests, if a custom Host: header is removed in a subsequent request, the second request would use...

CVE-2026-6276

A flaw was found in libcurl. This vulnerability allows for information disclosure when a custom Host: header is used in an initial HTTP request, and a subsequent request reuses the same connection without specifying a new Host: header. This can lead to libcurl incorrectly sending cookies intended...

CVE-2026-6429

A flaw was found in libcurl. When configured to use a .netrc file for credentials and follow HTTP redirects, libcurl can inadvertently send the password from the initial connection to the redirected host. This sensitive information disclosure occurs when both the original and redirect URLs use...

CVE-2026-5773

A flaw was found in libcurl. Due to a logical error in the connection reuse mechanism for SMB Server Message Block transfers, libcurl might reuse an existing SMB connection with a different share than intended. This vulnerability, categorized as CWE-488 Exposure of Data Element to Wrong Session,...

CVE-2026-5545

A flaw was found in libcurl. An application using libcurl that performs an authenticated HTTPS request after a Negotiate-authenticated one to the same host may incorrectly reuse the previous connection. This authentication bypass vulnerability allows the second request to be sent over a connectio...

CVE-2026-6429

When asked to both use a .netrc file for credentials and to follow HTTP redirects, libcurl could leak the password used for the first host to the followed-to host under certain circumstances...

UBUNTU-CVE-2026-5773

libcurl might in some circumstances reuse the wrong connection for SMBS transfers. libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection to avoid overhead. When reusing a connection a range of criteria must be met. Due to a logical error in the...

CVE-2026-6276

Using libcurl, when a custom Host: header is first set for an HTTP request and a second request is subsequently done using the same easy handle but without the custom Host: header set, the second request would use stale information and pass on cookies meant for the first host in the second reques...

CVE-2026-5545

libcurl might in some circumstances reuse the wrong connection when asked to do an authenticated HTTPS request after a Negotiate-authenticated one, when both use the same host. libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection to avoid...

UBUNTU-CVE-2026-6429

When asked to both use a .netrc file for credentials and to follow HTTP redirects, libcurl could leak the password used for the first host to the followed-to host under certain circumstances...

UBUNTU-CVE-2026-6276

Using libcurl, when a custom Host: header is first set for an HTTP request and a second request is subsequently done using the same easy handle but without the custom Host: header set, the second request would use stale information and pass on cookies meant for the first host in the second reques...

UBUNTU-CVE-2026-5545

libcurl might in some circumstances reuse the wrong connection when asked to do an authenticated HTTPS request after a Negotiate-authenticated one, when both use the same host. libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection to avoid...

cross-proxy Digest auth state leak

Successfully using libcurl to do a transfer over a specific HTTP proxy proxyA with Digest authentication and then changing the proxy host to a second one proxyB for a second transfer, reusing the same handle, makes libcurl wrongly pass on the Proxy-Authorization: header field meant for proxyA, to...

CURL-CVE-2026-6429 netrc credential leak with reused proxy connection

When asked to both use a .netrc file for credentials and to follow HTTP redirects, libcurl could leak the password used for the first host to the followed-to host under certain circumstances...

CURL-CVE-2026-7168 cross-proxy Digest auth state leak

Successfully using libcurl to do a transfer over a specific HTTP proxy proxyA with Digest authentication and then changing the proxy host to a second one proxyB for a second transfer, reusing the same handle, makes libcurl wrongly pass on the Proxy-Authorization: header field meant for proxyA, to...

netrc credential leak with reused proxy connection

When asked to both use a .netrc file for credentials and to follow HTTP redirects, libcurl could leak the password used for the first host to the followed-to host under certain circumstances...

stale custom cookie host causes cookie leak

Using libcurl, when a custom Host: header is first set for an HTTP request and a second request is subsequently done using the same easy handle but without the custom Host: header set, the second request would use stale information and pass on cookies meant for the first host in the second reques...

CURL-CVE-2026-6276 stale custom cookie host causes cookie leak

Using libcurl, when a custom Host: header is first set for an HTTP request and a second request is subsequently done using the same easy handle but without the custom Host: header set, the second request would use stale information and pass on cookies meant for the first host in the second reques...

PT-2026-35895

Name of the Vulnerable Software and Affected Versions curl affected versions not specified Description When using libcurl, a flaw exists where a custom Host: header set for an initial HTTP request can cause subsequent requests using the same easy handle to use stale information. If the second...

PT-2026-35893

Name of the Vulnerable Software and Affected Versions libcurl affected versions not specified Description A logical error in the connection pooling mechanism may cause libcurl to reuse an incorrect connection for SMBS transfers. When reusing a connection, specific criteria must be met; however, a...