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-2026-410

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-2026-399

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-2026-426 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-2026-419 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-2026-439 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-2026-401

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-2026-411 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-2026-388

A insufficiently protected credentials vulnerability in fixed in curl 7.83.0 might leak authentication or cookie header data on HTTP redirects to the same host but another port number...

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-2026-408

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-2026-407

A use after free vulnerability exists in curl v8.1.0 in the way libcurl offers a feature to verify an SSH server's public key using a SHA 256 hash. When this check fails, libcurl would free the memory for the fingerprint before it returns an error message containing the now freed hash. This flaw...

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-2026-398

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...

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-2026-386

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-2026-400

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-2026-420 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...