CVE-2026-86414

An HTTP proxy can trick libcurl into sending the origin's credentials Basic password, or a Negotiate/Kerberos ticket to the proxy itself, by answering the CONNECT tunnel request with 401 WWW-Authenticate: instead of the expected 407 Proxy-Authenticate:...

CVE-2026-86414

libcurl is vulnerable to a credential leak where an HTTP proxy can trick the library into sending the origin's credentials (such as Basic password or Negotiate/Kerberos tickets ) to the proxy itself. This occurs because the proxy can respond to a CONNECT tunnel request with a 401 WWW-Authenticate...

EUVD-2026-105306

An HTTP proxy can trick libcurl into sending the origin's credentials Basic password, or a Negotiate/Kerberos ticket to the proxy itself, by answering the CONNECT tunnel request with 401 WWW-Authenticate: instead of the expected 407 Proxy-Authenticate:...

CVE-2026-86414

An HTTP proxy can trick libcurl into sending the origin's credentials Basic password, or a Negotiate/Kerberos ticket to the proxy itself, by answering the "CONNECT" tunnel request with 401 "WWW-Authenticate:" instead of the expected 407 "Proxy-Authenticate:"...

CVE-2026-86414

An HTTP proxy can trick libcurl into sending the origin's credentials Basic password, or a Negotiate/Kerberos ticket to the proxy itself, by answering the CONNECT tunnel request with 401 WWW-Authenticate: instead of the expected 407 Proxy-Authenticate:...

EUVD-2026-105276

An ftp:// transfer configured with CURLUSESSLNONE can reuse a pooled FTP control connection that a previous easy handle upgraded with STARTTLS and authenticated using a client certificate. The second handle performs neither a new TLS handshake nor a new FTP login, so the server continues to...

CVE-2026-86411

An "ftp://" transfer configured with "CURLUSESSLNONE" can reuse a pooled FTP control connection that a previous easy handle upgraded with "STARTTLS" and authenticated using a client certificate. The second handle performs neither a new TLS handshake nor a new FTP login, so the server continues to...

CVE-2026-86409

Setting CURLOPTAWSSIGV4 to NULL but does not disable SigV4 authentication, contrary to expectations and documentation. A subsequent transfer on the same handle still sends an Authorization: AWS4-HMAC-SHA256 header to whatever URL isset next, leaking state information...

CVE-2026-86409

The curl library is vulnerable to a state leakage issue where setting CURLOPT_AWS_SIGV4 to NULL fails to disable SigV4 authentication as expected. Consequently, subsequent transfers on the same handle continue to send an Authorization: AWS4-HMAC-SHA256 header to unrelated URLs, potentially leakin...

EUVD-2026-105274

Setting CURLOPTAWSSIGV4 to NULL but does not disable SigV4 authentication, contrary to expectations and documentation. A subsequent transfer on the same handle still sends an Authorization: AWS4-HMAC-SHA256 header to whatever URL isset next, leaking state information...

CVE-2026-86409

Setting "CURLOPTAWSSIGV4" to NULL but does not disable SigV4 authentication, contrary to expectations and documentation. A subsequent transfer on the same handle still sends an "Authorization: AWS4-HMAC-SHA256" header to whatever URL isset next, leaking state information...

CVE-2026-86409

Setting CURLOPTAWSSIGV4 to NULL but does not disable SigV4 authentication, contrary to expectations and documentation. A subsequent transfer on the same handle still sends an Authorization: AWS4-HMAC-SHA256 header to whatever URL isset next, leaking state information...

curl: IDN decoding inserts authority delimiters and can redirect proxy CONNECT to a different host

IDN decoding can insert authority delimiters: CURLUPUNYCODE output does not round-trip and proxy requests carry an ambiguous authority Summary libcurl's IDN decoder accepts a hostname containing U+FF20 FULLWIDTH COMMERCIAL AT ＠. libidn2's TR46 transitional fallback converts it to ASCII @...

curl: A server response that answers nothing is used as the next transfer's reply — and with IMAP, a fully compliant server does this by accident

Name: Maturi Jaswanth Sai Madhu Mohan Product: curl / libcurl — all four pingpong protocols demonstrated: IMAP, POP3, SMTP and FTP — the same protocol set curl's own CVE-2026-92387 names Affected: reproduced on current git master dbb8262a9c 8.23.1-DEV, fetched and rebuilt today, on d1d4b5931a, on...

Ubuntu: USN-8927-1 (CVE-2026-87865): curl vulnerabilities

When libcurl uses libssh2 with a hashed knownhosts file, an unrelated initial entry can cause host key validation to report a key mismatch as a missing key to the CURLOPTSSHKEYFUNCTION callback...

Red Hat: CVE-2026-92388: curl: curl: FTP wildcard write callback mixup

When an FTP wildcard LIST operation fails, libcurl omits the restoration path meant for successful listings, leaving the write callback set to the internal listing parser and the write callback data pointing directly to the easy handle. Subsequent reuse of this handle triggers an immediate crash,...

Red Hat: CVE-2026-92389: curl: curl: TFTP direction confusion

libcurl's TFTP state machine fails to validate state transitions against the requested transfer direction, accepting opening server responses for both reads and writes interchangeably. A malicious TFTP server can respond to a download request in a way that forces the client into transmit mode,...

Red Hat: CVE-2026-92391: curl: curl: curl_mime_free stack overflow by recursion

A deeply nested multipart MIME structure constructed via the public API causes a stack overflow in libcurl during normal cleanup operations. An excessive recursion depth within curlmimefree leads to unbounded stack frame allocation during structure traversal, ultimately crashing the host process...

Red Hat: CVE-2026-94266: curl: curl: password leak in CURLINFO_EFFECTIVE_URL

libcurl could accidentally return a URL for curleasygetinfo's CURLINFOEFFECTIVEURL option containing credentials, even though neither the URL provided to libcurl nor the redirected URL did...

Ubuntu: USN-8927-1 (CVE-2026-92387): curl vulnerabilities

By permanently omitting the final control-response line, a malicious FTP, IMAP, POP3, or SMTP server can exploit libcurl and completely bypass its configured transfer timeout mechanism, indefinitely blocking all concurrent transfers bound to the same multi-handle...