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...

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...

libcurl 安全漏洞

libcurl is a free and easy-to-use client URL transfer library for cURL, which is open-source. There is a security vulnerability in libcurl, caused by improper handling of custom Host headers. This vulnerability may lead to the incorrect transmission of cookies from the first request during the...

libcurl 代码问题漏洞

libcurl is an open-source, free, and easy-to-use client URL transfer library for cURL. There are code vulnerabilities in libcurl, stemming from errors in connection reuse logic. These vulnerabilities may cause SMB transfers to incorrectly reuse existing connections to different shares, resulting ...

libcurl 代码问题漏洞

libcurl is an open-source, free, and easy-to-use client URL transfer library for cURL. There are code vulnerabilities in libcurl, stemming from a logical error in connection reuse logic. This error may lead to the incorrect reuse of connections that use different credentials after Negotiate...

Unity Linux 20.1060e / 20.1070e Security Update: curl (UTSA-2026-017594)

The Unity Linux 20 host has a package installed that is affected by a vulnerability as referenced in the UTSA-2026-017594 advisory. libcurl-using applications can ask for a specific client certificate to be used in a transfer. This is done with the CURLOPTSSLCERT option --cert with the command li...

JLSEC-2026-415 libcurl skips the certificate verification for a QUIC connection under certain conditions, when...

libcurl skips the certificate verification for a QUIC connection under certain conditions, when built to use wolfSSL. If told to use an unknown/bad cipher or curve, the error path accidentally skips the verification and returns OK, thus ignoring any certificate problems...

JLSEC-2026-434 Due to a mistake in libcurl's WebSocket code, a malicious server can send a particularly crafted...

Due to a mistake in libcurl's WebSocket code, a malicious server can send a particularly crafted packet which makes libcurl get trapped in an endless busy-loop. There is no other way for the application to escape or exit this loop other than killing the thread/process. This might be used to DoS...

JLSEC-2026-422 When libcurl is asked to perform automatic gzip decompression of content-encoded HTTP responses...

When libcurl is asked to perform automatic gzip decompression of content-encoded HTTP responses with the CURLOPTACCEPTENCODING option, using zlib 1.2.0.3 or older, an attacker-controlled integer overflow would make libcurl perform a buffer overflow...

JLSEC-2026-416 When an application tells libcurl it wants to allow HTTP/2 server push, and the amount of...

When an application tells libcurl it wants to allow HTTP/2 server push, and the amount of received headers for the push surpasses the maximum allowed limit 1000, libcurl aborts the server push. When aborting, libcurl inadvertently does not free all the previously allocated headers and instead lea...

JLSEC-2026-421 libcurl would wrongly close the same eventfd file descriptor twice when taking down a connection...

libcurl would wrongly close the same eventfd file descriptor twice when taking down a connection channel after having completed a threaded name resolve...

JLSEC-2026-417 libcurl did not check the server certificate of TLS connections done to a host specified as an IP...

libcurl did not check the server certificate of TLS connections done to a host specified as an IP address, when built to use mbedTLS. libcurl would wrongly avoid using the set hostname function when the specified hostname was given as an IP address, therefore completely skipping the certificate...

JLSEC-2026-396

When doing HTTPS transfers, libcurl might erroneously use the read callback CURLOPTREADFUNCTION to ask for data to send, even when the CURLOPTPOSTFIELDS option has been set, if the same handle previously was used to issue a PUT request which used that callback. This flaw may surprise the...

JLSEC-2026-427 When doing multi-threaded LDAPS transfers (LDAP over TLS) with libcurl, changing TLS options in...

When doing multi-threaded LDAPS transfers LDAP over TLS with libcurl, changing TLS options in one thread would inadvertently change them globally and therefore possibly also affect other concurrently setup transfers. Disabling certificate verification for a specific transfer could unintentionally...

JLSEC-2026-426 When using `CURLOPT_PINNEDPUBLICKEY` option with libcurl or `--pinnedpubkey` with the curl tool...

When using CURLOPTPINNEDPUBLICKEY option with libcurl or --pinnedpubkey with the curl tool,curl should check the public key of the server certificate to verify the peer. This check was skipped in a certain condition that would then make curl allow the connection without performing the proper chec...

JLSEC-2026-432 libcurl accidentally skips the certificate verification for QUIC connections when connecting to a...

libcurl accidentally skips the certificate verification for QUIC connections when connecting to a host specified as an IP address in the URL. Therefore, it does not detect impostors or man-in-the-middle attacks...

JLSEC-2026-390

libcurl provides the CURLOPTCERTINFO option to allow applications torequest details to be returned about a server's certificate chain.Due to an erroneous function, a malicious server could make libcurl built withNSS get stuck in a never-ending busy-loop when trying to retrieve thatinformation...

curl: libcurl: Information disclosure due to cookie leak when reusing connections with custom Host headers

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...

curl: libcurl: Wrong file transfer due to incorrect SMB connection reuse

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,...

curl: libcurl: Authentication bypass due to incorrect HTTP Negotiate connection reuse

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...