curl: 50: CMake `HTTP_ONLY` does not disable SSH backends — SCP and SFTP remain usable

Summary The CMake HTTPONLY=ON option is documented as "Disable all protocols except HTTP" CMakeLists.txt:538, but the implementation CMakeLists.txt:541-557 only sets CURLDISABLE flags for non-SSH protocols. It does not disable CURLUSELIBSSH2 or CURLUSELIBSSH. Since CURLUSELIBSSH2 defaults to ON, ...

curl: 42: `VMS_STS` macro typo (`< 3` vs `<< 3`) turns curl failures into successful OpenVMS conditions

Summary VMSSTS in src/toolvms.h line 46 uses a comparison 3 where a left-shift 3 is intended. This causes VMSSTSHIDE to evaluate to 0x10000001 instead of 0x10000000, setting bit 0 the OpenVMS success bit. When curl runs under DCL with --silent and without --show-error, the mask is ORed into the...

curl: 41: `main_checkfds()` pipe reuse leaks proxy credentials into HTTPS upload body

Summary When curl is launched with stdin fd 0 and stderr fd 2 closed, maincheckfds in src/toolmain.c can assign opposite ends of the same pipe to fd 0 and fd 2. In verbose mode with a stdin-based upload through an authenticated proxy, the Proxy-Authorization header written to stderr becomes...

curl: 18: Explicit IPv6 proxy zone ID silently ignored — proxy credentials sent to wrong interface

Explicit IPv6 proxy zone ID silently ignored — proxy credentials sent to wrong interface Summary When a proxy is configured with a literal link-local IPv6 address and an explicit zone ID e.g. http://fe80::1%25eth0:8080, curl parses and stores the zone correctly but never applies it to the socket...

curl: 07: GnuTLS 0-RTT early data bypasses file-backed public-key pin verification

GnuTLS 0-RTT early data bypasses file-backed public-key pin verification Summary When CURLSSLOPTEARLYDATA is enabled and CURLOPTPINNEDPUBLICKEY references a file path, replacing that file's contents between connections does not invalidate the TLS session cache. On the next connection, curl sends...

curl: 06: Incomplete fix for CVE-2026-7009: GCC/SecTrust builds silently discard stapled OCSP responses

Summary Curlvtlsappleverify in lib/vtls/apple.c passes the stapled OCSP response to SecTrustSetOCSPResponse only when both HAVEBUILTINAVAILABLE and SUPPORTSSecOCSP are defined. When HAVEBUILTINAVAILABLE is absent, the OCSP buffer is silently discarded. GCC does not support builtinavailable, so th...

curl: CVE-2026-82208: wolfSSL CA-cache hit overrides callback

Summary With the wolfSSL backend, when CA caching is enabled and an CURLOPTSSLCTXFUNCTION callback replaces the trust store, curl can silently reinstall the cached store after the callback returns. A certificate trusted by the cached store but rejected by the callback-selected store is then...

curl: CVE-2026-80255: secure cookie attribute bypass with tab

Summary A Set-Cookie header using HTAB horizontal tab instead of SPACE before the Secure attribute — e.g. Set-Cookie: sid=SECRET;\tSecure — causes curl to store the cookie without its Secure flag. The cookie is then sent over plaintext HTTP on subsequent requests to the same host. The...

curl: CVE-2026-82209: domain-scoped PSL domain cookie

Summary When libpsl is enabled and a response host is itself a public suffix e.g. github.io, a Set-Cookie header whose Domain attribute exactly equals that host is accepted by psliscookiedomainacceptable but stored with tailmatch = TRUE. RFC 6265 §5.3 requires this exact-match case to produce a...

curl: 46: `--libcurl` output carries `--insecure` across `--next` boundaries

Summary When --libcurl generates C source for a command that uses --next to separate multiple operations, local options from earlier operations leak into later ones. Specifically, if the first operation uses --insecure and the second does not, the generated program silently skips TLS certificate...

curl: 34: `curl_mprintf` reads `double` for documented `long double` conversions — uninitialized value disclosure

Summary docs/libcurl/curlmprintf.md documents that the L length modifier makes floating-point conversions %f, %e, %E, %g, %G accept a long double argument. The implementation in lib/mprintf.c recognizes L and sets FLAGSLONGDOUBLE, but the conversion switch %f/%e/%E/%g/%G unconditionally selects...

curl: 33: CONNECT_ONLY raw I/O selects wrong connection after CURLOPT_SHARE detach (incomplete fix for CVE-2020-8231)

Summary After a completed CURLOPTCONNECTONLY transfer, detaching the shared connection pool via curleasysetopteasy, CURLOPTSHARE, NULL causes curleasysend / curleasyrecv to silently operate on an unrelated connection from a different pool. Data intended for server B is sent to server A, and A's...

curl: 28: HTTP/3 UDP path ignores CURL_SOCKOPT_ALREADY_CONNECTED, reconnects callback-provided socket

Summary When CURLOPTSOCKOPTFUNCTION returns CURLSOCKOPTALREADYCONNECTED, the HTTP/3 QUIC UDP code path ignores it and calls connect anyway, silently reassociating the application-provided socket to a different peer. The TCP path has the correct check. This violates the documented callback contrac...

curl: Stacked --proto modifiers leave denied protocol enabled

Summary proto2num line 431–447 consumes only one leading modifier character via a switch statement. The documentation says entries may be "prefixed by zero or more modifiers." Before commit 86ac471d, a loop consumed all modifiers. The replacement switch reads only the first character. --proto...

curl: --etag-save - truncates append-redirected stdout

Summary saveetag line 267–273 calls fileno, fstat, ftruncatefd, 0 whenever the underlying fd is a regular file. It does not check OutStruct.regularfile, which is FALSE for stdout even when shell-redirected to a file. When --etag-save - is used with append redirection , an HTTP 2xx/3xx response...

curl: CVE-2026-80256: wcurl backslash bypass

A vulnerability was discovered in the wcurl script of the curl project. The vulnerability allowed an attacker-controlled URL to create a new file outside the directory chosen by a Windows user, subject to the user's filesystem permissions and the target not already existing. The vulnerability was...

curl: CVE-2026-80231: native CA store conn reuse

Summary nativecastore is in struct sslconfigdata line 73 of vtlsconfig.h, not sslprimaryconfig. matchsslprimaryconfig does not compare it. On macOS, Curlssleasyconfigcomplete line 258 auto-sets nativecastore = TRUE when no custom CA is configured — without modifying ssloptions. When CURLCABUNDLE ...

curl: CVE-2026-80230: OpenSSL pinning bypass

Summary Curlosslcheckpeercert line 4795 calls SSLget1peercertificate. When no peer certificate is available — as with anonymous cipher suites like AECDH-AES128-SHA — the function returns NULL. The subsequent guard at lines 4798–4799 checks !connconfig-verifypeer || connconfig-verifyhost; when bot...

curl: CVE-2026-80229: OpenSSL provider use-after-free

Summary When CURLOPTSSLENGINE is set e.g. "default" on OpenSSL 3.x, osslsetprovider line 1791 allocates a per-handle OSSLLIBCTX and stores it in data-state.libctx. During TLS connection setup, SSLCTXnewex line 3750 receives this library context and embeds a pointer to it inside the newly created...

curl: Unbound cross-peer HTTP Digest challenge state

Summary When libcurl parses an HTTP Digest WWW-Authenticate challenge, it stores the realm, nonce, algorithm, and qop into the easy handle's state.digest — but does not bind that state to the peer that sent it. If the challenge is parsed but never used for output e.g. because Basic or Bearer was...