1717 matches found
JLSEC-2026-391
libcurl would reuse a previously created connection even when a TLS or SSHrelated option had been changed that should have prohibited reuse.libcurl keeps previously used connections in a connection pool for subsequenttransfers to reuse if one of them matches the setup. However, several TLS andSSH...
JLSEC-2026-393
curl 7.84.0 supports "chained" HTTP compression algorithms, meaning that a serverresponse can be compressed multiple times and potentially with different algorithms. The number of acceptable "links" in this "decompression chain" was unbounded, allowing a malicious server to insert a virtually...
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-2026-426 When using `CURLOPT_PINNEDPUBLICKEY` option with libcurl or `--pinnedpubkey` with the curl tool,curl...
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-2026-394
When curl 7.84.0 saves cookies, alt-svc and hsts data to local files, it makes the operation atomic by finalizing the operation with a rename from a temporary name to the final target file name.In that rename operation, it might accidentally widen the permissions for the target file, leaving the...
JLSEC-2026-418 When curl is told to use the Certificate Status Request TLS extension, often referred to as OCSP...
When curl is told to use the Certificate Status Request TLS extension, often referred to as OCSP stapling, to verify that the server certificate is valid, it might fail to detect some OCSP problems and instead wrongly consider the response as fine. If the returned status reports another error tha...
JLSEC-2026-425 URLs containing percent-encoded slashes (`/` or `\ `) can trick wcurl into saving the output file...
URLs containing percent-encoded slashes / or \ can trick wcurl into saving the output file outside of the current directory without the user explicitly asking for it. This flaw only affects the wcurl command line tool...
JLSEC-2026-422 When libcurl is asked to perform automatic gzip decompression of content-encoded HTTP responses with...
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-2026-417 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-2026-397
When curl is used to retrieve and parse cookies from a HTTPS server, itaccepts cookies using control codes that when later are sent back to a HTTPserver might make the server return 400 responses. Effectively allowing a"sister site" to deny service to all siblings...
JLSEC-2026-399
In curl before 7.86.0, the HSTS check could be bypassed to trick it into staying with HTTP. Using its HSTS support, curl can be instructed to use HTTPS directly instead of using an insecure cleartext HTTP step even when HTTP is provided in the URL. This mechanism could be bypassed if the host nam...
JLSEC-2026-400
A vulnerability exists in curl 7.87.0 HSTS check that could be bypassed to trick it to keep using HTTP. Using its HSTS support, curl can be instructed to use HTTPS instead of using an insecure clear-text HTTP step even when HTTP is provided in the URL. However, the HSTS mechanism could be bypasse...
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-2026-431 When doing SSH-based transfers using either SCP or SFTP, and asked to do public key authentication,...
When doing SSH-based transfers using either SCP or SFTP, and asked to do public key authentication, curl would wrongly still ask and authenticate using a locally running SSH agent...
JLSEC-2026-439 When doing a second SMB request to the same host again, curl would wrongly use a data pointer...
When doing a second SMB request to the same host again, curl would wrongly use a data pointer pointing into already freed memory...
JLSEC-2026-429 When doing TLS related transfers with reused easy or multi handles and altering the...
When doing TLS related transfers with reused easy or multi handles and altering the CURLSSLOPTNOPARTIALCHAIN option, libcurl could accidentally reuse a CA store cached in memory for which the partial chain option was reversed. Contrary to the user's wishes and expectations. This could make libcur...
JLSEC-2026-424 curl's code for managing SSH connections when SFTP was done using the wolfSSH powered backend was...
curl's code for managing SSH connections when SFTP was done using the wolfSSH powered backend was flawed and missed host verification mechanisms. This prevents curl from detecting MITM attackers and more...
JLSEC-2026-414 When a protocol selection parameter option disables all protocols without adding any then the...
When a protocol selection parameter option disables all protocols without adding any then the default set of protocols would remain in the allowed set due to an error in the logic for removing protocols. The below command would perform a request to curl.se with a plaintext protocol which has been...
JLSEC-2026-413 When asked to both use a `.netrc` file for credentials and to follow HTTP redirects, curl could leak...
When asked to both use a .netrc file for credentials and to follow HTTP redirects, curl could leak the password used for the first host to the followed-to host under certain circumstances. This flaw only manifests itself if the netrc file has an entry that matches the redirect target hostname but...
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-2026-438 curl would wrongly reuse an existing HTTP proxy connection doing CONNECT to a server, even if the...
curl would wrongly reuse an existing HTTP proxy connection doing CONNECT to a server, even if the new request uses different credentials for the HTTP proxy. The proper behavior is to create or use a separate connection...
JLSEC-2026-412 curl inadvertently kept the SSL session ID for connections in its cache even when the verify status...
curl inadvertently kept the SSL session ID for connections in its cache even when the verify status OCSP stapling test failed. A subsequent transfer to the same hostname could then succeed if the session ID cache was still fresh, which then skipped the verify status check...
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-2026-405
A vulnerability in input validation exists in curl 8.0 during communication using the TELNET protocol may allow an attacker to pass on maliciously crafted user name and "telnet options" during server negotiation. The lack of proper input scrubbing allows an attacker to send content or perform...
JLSEC-2026-419 When curl is asked to use HSTS, the expiry time for a subdomain might overwrite a parent domain's...
When curl is asked to use HSTS, the expiry time for a subdomain might overwrite a parent domain's cache entry, making it end sooner or later than otherwise intended. This affects curl using applications that enable HSTS and use URLs with the insecure HTTP:// scheme and perform transfers with host...
JLSEC-2026-408
A denial of service vulnerability exists in curl v8.1.0 in the way libcurl provides several different backends for resolving host names, selected at build time. If it is built to use the synchronous resolver, it allows name resolves to time-out slow operations using alarm and siglongjmp. When doi...
JLSEC-2026-389
The curl URL parser wrongly accepts percent-encoded URL separators like '/'when decoding the host name part of a URL, making it a different URL usingthe wrong host name when it is later retrieved.For example, a URL like http://example.com%2F127.0.0.1/, would be allowed bythe parser and get...
JLSEC-2026-387
An information disclosure vulnerability exists in curl 7.65.0 to 7.82.0 are vulnerable that by using an IPv6 address that was in the connection pool but with a different zone id it could reuse a connection instead...
JLSEC-2026-409
An improper certificate validation vulnerability exists in curl v8.1.0 in the way it supports matching of wildcard patterns when listed as "Subject Alternative Name" in TLS server certificates. curl can be built to use its own name matching function for TLS rather than one provided by a TLS...
JLSEC-2026-427 When doing multi-threaded LDAPS transfers (LDAP over TLS) with libcurl, changing TLS options in one...
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-2026-435 1
A cookie is set using the secure keyword for https://target 2. curl is redirected to or otherwise made to speak with http://target same hostname, but using clear text HTTP using the same cookie set 3. The same cookie name is set - but with just a slash as path path="/",. Since this site is not...
JLSEC-2026-406
A path traversal vulnerability exists in curl 8.0.0 SFTP implementation causes the tilde character to be wrongly replaced when used as a prefix in the first path element, in addition to its intended use as the first element to indicate a path relative to the user's home directory. Attackers can...
JLSEC-2026-410
An information disclosure vulnerability exists in curl v8.1.0 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 wasused to issue a PUT request...
JLSEC-2026-385
An improper authentication vulnerability exists in curl 7.33.0 to and including 7.82.0 which might allow reuse OAUTH2-authenticated connections without properly making sure that the connection was authenticated with the same credentials as set for this transfer. This affects SASL-enabled protocol...
JLSEC-2026-395
When curl 7.84.0 does FTP transfers secured by krb5, it handles message verification failures wrongly. This flaw makes it possible for a Man-In-The-Middle attack to go unnoticed and even allows it to inject data to the client...
JLSEC-2026-436
libcurl can in some circumstances reuse the wrong connection when asked to do an Negotiate-authenticated HTTP or HTTPS request. 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...
JLSEC-2026-411 This flaw allows a malicious HTTP server to set "super cookies" in curl that are then passed back to...
This flaw allows a malicious HTTP server to set "super cookies" in curl that are then passed back to more origins than what is otherwise allowed or possible. This allows a site to set cookies that then would get sent to different and unrelated sites and domains. It could do this by exploiting a...
JLSEC-2026-428 When an OAuth2 bearer token is used for an HTTP(S) transfer, and that transfer performs a...
When an OAuth2 bearer token is used for an HTTPS transfer, and that transfer performs a cross-protocol redirect to a second URL that uses an IMAP, LDAP, POP3 or SMTP scheme, curl might wrongly pass on the bearer token to the new target host...
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...
JLSEC-2026-430 When doing SSH-based transfers using either SCP or SFTP, and setting the `known_hosts` file, libcurl...
When doing SSH-based transfers using either SCP or SFTP, and setting the knownhosts file, libcurl could still mistakenly accept connecting to hosts not present in the specified file if they were added as recognized in the libssh global knownhosts file...
JLSEC-2026-402
A cleartext transmission of sensitive information vulnerability exists in curl v7.88.0 that could cause HSTS functionality fail when multiple URLs are requested serially. Using its HSTS support, curl can be instructed to use HTTPS instead of usingan insecure clear-text HTTP step even when HTTP is...
JLSEC-2026-404
An allocation of resources without limits or throttling vulnerability exists in curl v7.88.0 based on the "chained" HTTP compression algorithms, meaning that a server response can be compressed multiple times and potentially with differentalgorithms. The number of acceptable "links" in this...
JLSEC-2026-433 libcurl supports *pinning* of the server certificate public key for HTTPS transfers
libcurl supports pinning of the server certificate public key for HTTPS transfers. Due to an omission, this check is not performed when connecting with QUIC for HTTP/3, when the TLS backend is wolfSSL. Documentation says the option works with wolfSSL, failing to specify that it does not for QUIC...
JLSEC-2026-386
An insufficiently protected credentials vulnerability exists in curl 4.9 to and include curl 7.82.0 are affected that could allow an attacker to extract credentials when follows HTTPS redirects is used with authentication could leak credentials to other services that exist on different protocols ...
JLSEC-2026-437 When an OAuth2 bearer token is used for an HTTP(S) transfer, and that transfer performs a redirect...
When an OAuth2 bearer token is used for an HTTPS transfer, and that transfer performs a redirect to a second URL, curl could leak that token to the second hostname under some circumstances. If the hostname that the first request is redirected to has information in the used .netrc file, with eithe...
JLSEC-2026-392
A malicious server can serve excessive amounts of Set-Cookie: headers in a HTTP response to curl and curl 7.84.0 stores all of them. A sufficiently large amount of big cookies make subsequent HTTP requests to this, or other servers to which the cookies match, create requests that become larger th...
JLSEC-2026-423 curl's websocket code did not update the 32 bit mask pattern for each new outgoing frame as the...
curl's websocket code did not update the 32 bit mask pattern for each new outgoing frame as the specification says. Instead it used a fixed mask that persisted and was used throughout the entire connection. A predictable mask pattern allows for a malicious server to induce traffic between the two...
JLSEC-2026-401
A use after free vulnerability exists in curl 7.87.0. Curl can be asked to tunnel virtually all protocols it supports through an HTTP proxy. HTTP proxies can and often do deny such tunnel operations. When getting denied to tunnel the specific protocols SMB or TELNET, curl would use a heap-allocat...
JLSEC-2026-420 When asked to use a `.netrc` file for credentials **and** to follow HTTP redirects, curl could leak...
When asked to use a .netrc file for credentials and to follow HTTP redirects, curl could leak the password used for the first host to the followed-to host under certain circumstances. This flaw only manifests itself if the netrc file has a default entry that omits both login and password. A rare...
JLSEC-2026-398
curl before 7.86.0 has a double free. If curl is told to use an HTTP proxy for a transfer with a non-HTTPS URL, it sets up the connection to the remote server by issuing a CONNECT request to the proxy, and then tunnels the rest of the protocol through. An HTTP proxy might refuse this request HTTP...