Libcurl Security Vulnerabilities

CVE-2023-38545

This flaw makes curl overflow a heap based buffer in the SOCKS5 proxy handshake. When curl is asked to pass along the host name to the SOCKS5 proxy to allow that to resolve the address instead of it getting done by curl itself, the maximum length that host name can be is 255 bytes. If the host...

CVE-2023-38546

This flaw allows an attacker to insert cookies at will into a running program using libcurl, if the specific series of conditions are met. libcurl performs transfers. In its API, an application creates "easy handles" that are the individual handles for single transfers. libcurl provides a function....

CVE-2023-27535

An authentication bypass vulnerability exists in libcurl <8.0.0 in the FTP connection reuse feature that can result in wrong credentials being used during subsequent transfers. Previously created connections are kept in a connection pool for reuse if they match the current setup. However, certai...

CVE-2023-27537

A double free vulnerability exists in libcurl <8.0.0 when sharing HSTS data between separate "handles". This sharing was introduced without considerations for do this sharing across separate threads but there was no indication of this fact in the documentation. Due to missing mutexes or thread.....

CVE-2023-27536

An authentication bypass vulnerability exists libcurl <8.0.0 in the connection reuse feature which can reuse previously established connections with incorrect user permissions due to a failure to check for changes in the CURLOPT_GSSAPI_DELEGATION option. This vulnerability affects...

CVE-2023-27538

An authentication bypass vulnerability exists in libcurl prior to v8.0.0 where it reuses a previously established SSH connection despite the fact that an SSH option was modified, which should have prevented reuse. libcurl maintains a pool of previously used connections to reuse them for subsequent....

CVE-2021-22945

When sending data to an MQTT server, libcurl <= 7.73.0 and 7.78.0 could in some circumstances erroneously keep a pointer to an already freed memory area and both use that again in a subsequent call to send data and also free it...

CVE-2021-22924

libcurl keeps previously used connections in a connection pool for subsequenttransfers to reuse, if one of them matches the setup.Due to errors in the logic, the config matching function did not take 'issuercert' into account and it compared the involved paths case insensitively,which could lead...

CVE-2021-22876

curl 7.1.1 to and including 7.75.0 is vulnerable to an "Exposure of Private Personal Information to an Unauthorized Actor" by leaking credentials in the HTTP Referer: header. libcurl does not strip off user credentials from the URL when automatically populating the Referer: HTTP request header...

CVE-2021-22890

curl 7.63.0 to and including 7.75.0 includes vulnerability that allows a malicious HTTPS proxy to MITM a connection due to bad handling of TLS 1.3 session tickets. When using a HTTPS proxy and TLS 1.3, libcurl can confuse session tickets arriving from the HTTPS proxy but work as if they arrived...

CVE-2020-8286

curl 7.41.0 through 7.73.0 is vulnerable to an improper check for certificate revocation due to insufficient verification of the OCSP...

CVE-2020-8285

curl 7.21.0 to and including 7.73.0 is vulnerable to uncontrolled recursion due to a stack overflow issue in FTP wildcard match...

CVE-2020-8231

Due to use of a dangling pointer, libcurl 7.29.0 through 7.71.1 can use the wrong connection when sending...

CVE-2019-5436

A heap buffer overflow in the TFTP receiving code allows for DoS or arbitrary code execution in libcurl versions 7.19.4 through...

CVE-2019-3823

libcurl versions from 7.34.0 to before 7.64.0 are vulnerable to a heap out-of-bounds read in the code handling the end-of-response for SMTP. If the buffer passed to smtp_endofresp() isn't NUL terminated and contains no character ending the parsed number, and len is set to 5, then the strtol() call....

CVE-2019-3822

libcurl versions from 7.36.0 to before 7.64.0 are vulnerable to a stack-based buffer overflow. The function creating an outgoing NTLM type-3 header (lib/vauth/ntlm.c:Curl_auth_create_ntlm_type3_message()), generates the request HTTP header contents based on previously received data. The check that....

CVE-2018-16890

libcurl versions from 7.36.0 to before 7.64.0 is vulnerable to a heap buffer out-of-bounds read. The function handling incoming NTLM type-2 messages (lib/vauth/ntlm.c:ntlm_decode_type2_target) does not validate incoming data correctly and is subject to an integer overflow vulnerability. Using that....

CVE-2018-14618

curl before version 7.61.1 is vulnerable to a buffer overrun in the NTLM authentication code. The internal function Curl_ntlm_core_mk_nt_hash multiplies the length of the password by two (SUM) to figure out how large temporary storage area to allocate from the heap. The length value is then...

CVE-2016-8622

The URL percent-encoding decode function in libcurl before 7.51.0 is called curl_easy_unescape. Internally, even if this function would be made to allocate a unscape destination buffer larger than 2GB, it would return that new length in a signed 32 bit integer variable, thus the length would get...

CVE-2017-7468

In curl and libcurl 7.52.0 to and including 7.53.1, libcurl would attempt to resume a TLS session even if the client certificate had changed. That is unacceptable since a server by specification is allowed to skip the client certificate check on resume, and may instead use the old identity which...

CVE-2018-1000005

libcurl 7.49.0 to and including 7.57.0 contains an out bounds read in code handling HTTP/2 trailers. It was reported (https://github.com/curl/curl/pull/2231) that reading an HTTP/2 trailer could mess up future trailers since the stored size was one byte less than required. The problem is that the.....

CVE-2017-8816

The NTLM authentication feature in curl and libcurl before 7.57.0 on 32-bit platforms allows attackers to cause a denial of service (integer overflow and resultant buffer overflow, and application crash) or possibly have unspecified other impact via vectors involving long user and password...

CVE-2017-8817

The FTP wildcard function in curl and libcurl before 7.57.0 allows remote attackers to cause a denial of service (out-of-bounds read and application crash) or possibly have unspecified other impact via a string that ends with an '['...

CVE-2017-8818

curl and libcurl before 7.57.0 on 32-bit platforms allow attackers to cause a denial of service (out-of-bounds access and application crash) or possibly have unspecified other impact because too little memory is allocated for interfacing to an SSL...

CVE-2017-1000257

An IMAP FETCH response line indicates the size of the returned data, in number of bytes. When that response says the data is zero bytes, libcurl would pass on that (non-existing) data with a pointer and the size (zero) to the deliver-data function. libcurl's deliver-data function treats zero as a.....

CVE-2017-1000254

libcurl may read outside of a heap allocated buffer when doing FTP. When libcurl connects to an FTP server and successfully logs in (anonymous or not), it asks the server for the current directory with the PWD command. The server then responds with a 257 response containing the path, inside double....

CVE-2017-1000100

When doing a TFTP transfer and curl/libcurl is given a URL that contains a very long file name (longer than about 515 bytes), the file name is truncated to fit within the buffer boundaries, but the buffer size is still wrongly updated to use the untruncated length. This too large value is then...

CVE-2017-1000099

When asking to get a file from a file:// URL, libcurl provides a feature that outputs meta-data about the file using HTTP-like headers. The code doing this would send the wrong buffer to the user (stdout or the application's provide callback), which could lead to other private data from the heap...

CVE-2016-7167

Multiple integer overflows in the (1) curl_escape, (2) curl_easy_escape, (3) curl_unescape, and (4) curl_easy_unescape functions in libcurl before 7.50.3 allow attackers to have unspecified impact via a string of length 0xffffffff, which triggers a heap-based buffer...

CVE-2016-7141

curl and libcurl before 7.50.2, when built with NSS and the libnsspem.so library is available at runtime, allow remote attackers to hijack the authentication of a TLS connection by leveraging reuse of a previously loaded client certificate from file for a connection for which no certificate has...

CVE-2016-5421

Use-after-free vulnerability in libcurl before 7.50.1 allows attackers to control which connection is used or possibly have unspecified other impact via unknown...

CVE-2016-5420

curl and libcurl before 7.50.1 do not check the client certificate when choosing the TLS connection to reuse, which might allow remote attackers to hijack the authentication of the connection by leveraging a previously created connection with a different client...

CVE-2016-5419

curl and libcurl before 7.50.1 do not prevent TLS session resumption when the client certificate has changed, which allows remote attackers to bypass intended restrictions by resuming a...

CVE-2015-3237

The smb_request_state function in cURL and libcurl 7.40.0 through 7.42.1 allows remote SMB servers to obtain sensitive information from memory or cause a denial of service (out-of-bounds read and crash) via crafted length and offset...

CVE-2015-3236

cURL and libcurl 7.40.0 through 7.42.1 send the HTTP Basic authentication credentials for a previous connection when reusing a reset (curl_easy_reset) connection handle to send a request to the same host name, which allows remote attackers to obtain sensitive information via unspecified...

CVE-2015-3153

The default configuration for cURL and libcurl before 7.42.1 sends custom HTTP headers to both the proxy and destination server, which might allow remote proxy servers to obtain sensitive information by reading the header...

CVE-2015-3148

cURL and libcurl 7.10.6 through 7.41.0 do not properly re-use authenticated Negotiate connections, which allows remote attackers to connect as other users via a...

CVE-2015-3145

The sanitize_cookie_path function in cURL and libcurl 7.31.0 through 7.41.0 does not properly calculate an index, which allows remote attackers to cause a denial of service (out-of-bounds write and crash) or possibly have other unspecified impact via a cookie path containing only a double-quote...

CVE-2015-3144

The fix_hostname function in cURL and libcurl 7.37.0 through 7.41.0 does not properly calculate an index, which allows remote attackers to cause a denial of service (out-of-bounds read or write and crash) or possibly have other unspecified impact via a zero-length host name, as demonstrated by...

CVE-2015-3143

cURL and libcurl 7.10.6 through 7.41.0 does not properly re-use NTLM connections, which allows remote attackers to connect as other users via an unauthenticated request, a similar issue to...

CVE-2014-8151

The darwinssl_connect_step1 function in lib/vtls/curl_darwinssl.c in libcurl 7.31.0 through 7.39.0, when using the DarwinSSL (aka SecureTransport) back-end for TLS, does not check if a cached TLS session validated the certificate when reusing the session, which allows man-in-the-middle attackers...

CVE-2014-8150

CRLF injection vulnerability in libcurl 6.0 through 7.x before 7.40.0, when using an HTTP proxy, allows remote attackers to inject arbitrary HTTP headers and conduct HTTP response splitting attacks via CRLF sequences in a...

CVE-2014-3620

cURL and libcurl before 7.38.0 allow remote attackers to bypass the Same Origin Policy and set cookies for arbitrary sites by setting a cookie for a top-level...

CVE-2014-3613

cURL and libcurl before 7.38.0 does not properly handle IP addresses in cookie domain names, which allows remote attackers to set cookies for or send arbitrary cookies to certain sites, as demonstrated by a site at 192.168.0.1 setting cookies for a site at...

CVE-2014-3707

The curl_easy_duphandle function in libcurl 7.17.1 through 7.38.0, when running with the CURLOPT_COPYPOSTFIELDS option, does not properly copy HTTP POST data for an easy handle, which triggers an out-of-bounds read that allows remote web servers to read sensitive memory...

CVE-2014-2522

curl and libcurl 7.27.0 through 7.35.0, when running on Windows and using the SChannel/Winssl TLS backend, does not verify that the server hostname matches a domain name in the subject's Common Name (CN) or subjectAltName field of the X.509 certificate when accessing a URL that uses a numerical IP....

CVE-2014-0138

The default configuration in cURL and libcurl 7.10.6 before 7.36.0 re-uses (1) SCP, (2) SFTP, (3) POP3, (4) POP3S, (5) IMAP, (6) IMAPS, (7) SMTP, (8) SMTPS, (9) LDAP, and (10) LDAPS connections, which might allow context-dependent attackers to connect as other users via a request, a similar issue.....

CVE-2014-0139

cURL and libcurl 7.1 before 7.36.0, when using the OpenSSL, axtls, qsossl or gskit libraries for TLS, recognize a wildcard IP address in the subject's Common Name (CN) field of an X.509 certificate, which might allow man-in-the-middle attackers to spoof arbitrary SSL servers via a crafted...

CVE-2014-0015

cURL and libcurl 7.10.6 through 7.34.0, when more than one authentication method is enabled, re-uses NTLM connections, which might allow context-dependent attackers to authenticate as other users via a...

CVE-2013-6422

The GnuTLS backend in libcurl 7.21.4 through 7.33.0, when disabling digital signature verification (CURLOPT_SSL_VERIFYPEER), also disables the CURLOPT_SSL_VERIFYHOST check for CN or SAN host name fields, which makes it easier for remote attackers to spoof servers and conduct man-in-the-middle...