curl: Trailing-Dot Hostname in Redirect Silently Strips Client Certificate and Auth Credentials

Summary When curl follows a redirect where the Location header contains a hostname with a trailing dot e.g., https://example.com./path, Curlpeerequal in peer.c:321-330 compares the original hostname example.com against the redirect target example.com. using curlstrequal, which does not normalize...

curl: curl-ipv4-percent-normalization-SSRF

Summary: six or fewer sentences describing the issue in your own human voice and optionally a short proof-of-concept script Affected version Which curl/libcurl version are you using to reproduce? On which platform? curl -V typically generates good output to include Steps To Reproduce: add details...

curl: SSH/SFTP connection reuse can bypass SSH key identity after ssh_config_matches removal

Summary: libcurl's SSH/SFTP connection reuse logic no longer binds a pooled SSH connection to the SSH key identity requested by the new transfer. After sshconfigmatches was removed, urlmatchprotoconfig again has no SSH-specific check for CURLOPTSSHPUBLICKEYFILE or CURLOPTSSHPRIVATEKEYFILE. An...

curl: SOCKS5 no-auth accepted despite username/password-only authentication

Summary: curl/libcurl appears to allow unauthenticated SOCKS5 negotiation even when the caller explicitly configures username/password-only SOCKS5 authentication. With --socks5-basic and SOCKS5 credentials set, curl still advertises both SOCKS5 method 0x00 no authentication and 0x02...

curl: libcurl: HTTP/1.x bare LF byte in response header value enables cookie jar pollution and POST body/credential exfiltration via redirect — RC=0, curl 8

Summary curl's HTTP/1.x response header parser splits header lines using a single memchrbuf, '\n', blen call lib/http.c:4457, with no awareness of whether the current position is inside a quoted-string value. A server response containing any header field whose value embeds a raw LF byte \x0a caus...

curl: GnuTLS OCSP stapling accepts unrelated SingleResponse (no cert-ID binding)

Summary This report describes a variant of the publicly disclosed curl vulnerability CVE-2020-8286 OCSP stapling verification bypass, found in the GnuTLS TLS backend lib/vtls/gtls.c. The original CVE affected the NSS backend; this variant reproduces the same logical class of defect — accepting...

curl: OpenSSL TLS 1.2 session resumption accepts expired server certificates in libcurl

Summary curl's OpenSSL backend can accept a new TLS 1.2 HTTPS connection after the server certificate has expired if the connection resumes a previously cached TLS session. A full handshake made at the same time with the same certificate fails with CURLEPEERFAILEDVERIFICATION, but the resumed...

Node.js: Incomplete Fix for CVE-2026-21637: OCSPRequest and resumeSession Events Crash Node.js TLS Server via Unhandled Synchronous Exceptions

Summary The March 2026 security release patched CVE-2026-21637 by wrapping SNICallback, ALPNCallback, and pskCallback invocations in try/catch blocks inside lib/internal/tls/wrap.js. That fix is present in v26.3.0. However, two other TLS callback paths in the same file were left unprotected: 1...

curl: DNS domain search list followed for extant domain missing A or AAAA records

Summary: Curl calls getaddrinfo to resolve a domain's addresses, however glibc will continue though the domain search list to find data even if it gets a NODATA response. When using AFUNSPEC in the aihints, this search will stop at the first domain with either an A or AAAA record, however when...

curl: PRE_PROXY change leaks stale Proxy Digest state across proxy-chain boundary

Summary After a Digest-authenticated HTTP proxy transfer, changing only CURLOPTPREPROXY on the same libcurl easy handle does not clear stale proxy Digest/auth state. If the new SOCKS pre-proxy resolves the same HTTP proxy hostname to a different proxy endpoint, the second proxy receives a...

curl: RTSP Digest auth state leaks across origins on reused libcurl easy handle

Summary When a reused libcurl easy handle first authenticates to one RTSP origin with Digest authentication and is then switched to a different RTSP origin, libcurl can send the old origin's Digest authentication state to the new origin. The second RTSP server does not need to send a...

curl: TFTP upload ignores --continue-at / CURLOPT_RESUME_FROM and leaks skipped local file prefix

Summary TFTP uploads ignore the configured resume offset. When a caller runs curl -C N -T file tftp://... or uses libcurl with CURLOPTUPLOAD and CURLOPTRESUMEFROM, curl should skip the first N bytes of the local source before uploading. Instead, the TFTP code sends the complete local file from by...

PortSwigger Web Security: Incomplete fix for CVE-2022-35406: meta-redirect content-type check bypassable via parameter injection

The fix for CVE-2022-35406 1541301 stops Burp from following a redirect when the response Content-Type/Content-Disposition would prevent HTML rendering. The check substring-matches html in the raw Content-Type instead of parsing the media type. A text/plain response can smuggle the token via a...

curl: libcurl 8.20.0 ignores HTTP Digest domain protection space and preemptively leaks Digest auth outside the declared scope

Summary: libcurl 8.20.0 ignores the server-declared HTTP Digest domain protection space for origin authentication and reuses stored Digest state too broadly on the same easy handle. After a successful Digest-authenticated request, a later request on the same easy handle can receive a preemptive...

curl: heap-use-after-free in state.referer when CURLOPT_REFERER replaced or cleared after perform

Calling curleasysetoptcurl, CURLOPTREFERER, ... to replace or clear a previously-set referer after curleasyperform frees the old string via Curlsetstropt lib/setopt.c:87 but leaves data-state.referer.ptr pointing at the freed heap region. curleasygetinfoCURLINFOREFERER and curleasyduphandle then...

curl: curl/libcurl 8.20.0 NOPROXY bypass via uppercase-hex IPv4 aliases leaks off-proxy Basic credentials to the configured proxy

Summary: curl/libcurl 8.20.0 fails to enforce CURLOPTNOPROXY, --noproxy, and NOPROXY consistently for uppercase-hex IPv4 aliases such as 0X7f.1 on glibc-based systems that accept these legacy numeric IPv4 forms. When a canonical IP literal is excluded from proxying, curl sends the canonical form...

curl: SMTP connection reuse ignores --ssl-reqd / CURLOPT_USE_SSL and reuses a clear-text STARTTLS session on current master

Summary: Current master reintroduces a STARTTLS connection-reuse bug in SMTP. After commit 91dcf4e610 url: urlmatchdestination fix, curl/libcurl can reuse an already-established clear-text smtp:// session for a later logical request that explicitly requires TLS via --ssl-reqd or CURLOPTUSESSL =...

curl: Low priority HSTS bypass in curl_easy_duphandle()

Summary: curleasyduphandle creates a fresh HSTS store for the cloned handle and populates it from the configured files and callbacks, but never copies entries acquired from Strict-Transport-Security response headers during the parent's lifetime. This means the client using a cloned handle may...

curl: Proxy CONNECT response poisoning via authentication retry in cf-h1-proxy.c (libcurl)

Summary: When an HTTP/1.x proxy returns a 407 with no Content-Length and no chunked transfer-encoding, lib/cf-h1-proxy.c singleheader sets ts-keepon = KEEPONDONE but never sets ts-closeconnection = TRUE. Because ts-closeconnection and conn-bits.close both stay false, the CONNECT tunnel state...

curl: curl External-Controlled Filename in `--url @file` Leads to Arbitrary File Overwrite

Vulnerability Report: curl External-Controlled Filename in --url @file Leads to Arbitrary File Overwrite 1. Product Overview curl is a widely used command-line tool and library libcurl for transferring data with URL syntax across multiple protocols such as HTTP, HTTPS, and FTP. It is preinstalled...

curl: CURLOPT_COOKIE leaked to cross-origin redirect target — CURLOPT_UNRESTRICTED_AUTH bypass for the STRING_COOKIE path

Summary: httpcookies at lib/http.c:2532-2534 appends the value of CURLOPTCOOKIE the cookie supplied via -b to outgoing Cookie: headers without invoking Curlauthallowedtohost. As a result, when CURLOPTFOLLOWLOCATION is enabled and the initial origin issues a cross-origin redirect open redirector,...

curl: Mentioned unites are at the same time .Then we have to increase the bounty.

Summary: Once you done with the coding then we have to increase the bounty and then write the reviwe on the same Once we find the error then we have to submit the margin and find the events Affected version Use a language that is not susceptible to these issues. However, be careful of null byte...

curl: TLS conn reuse and session cache ignore fsslctx callback and ssl_config_data flags ( incomplete fix variant of 7541ae569 )

Summary matchsslprimaryconfig in lib/vtls/vtls.c:194 and the session-cache key built by cfsslpeerkeybuild in lib/vtls/vtlsscache.c:240 both compare only struct sslprimaryconfig fields when deciding whether to reuse a TLS connection or cached session. Several fields that materially change the TLS...

curl: lib/ldap.c follows attacker-controlled LDAP referrals and binds to a second server; WinLDAP builds leak current logon credentials (confirmed on Window

Summary: curl's generic LDAP backend lib/ldap.c does not disable automatic LDAP referral chasing, unlike lib/openldap.c, which explicitly sets LDAPOPTREFERRALS to LDAPOPTOFF. As a result, a malicious first-hop LDAP server can return a referral to an attacker-controlled second LDAP server and caus...

curl: curl GnuTLS backend accepts a clientAuth-only certificate for HTTPS server authentication

Summary: When curl/libcurl is built with the GnuTLS backend, the current HTTPS server-certificate validation path verifies the trust chain and hostname but does not enforce TLS server Extended Key Usage semantics. As a result, a leaf certificate that chains to a trusted CA, matches the requested...

Node.js: Memory Corruption via TOCTOU Race in SharedArrayBuffer UTF-8 Decode (`StringBytes::Encode`)

I discovered a memory corruption vulnerability in Node.js's native UTF-8 string decoding path src/stringbytes.cc. When Buffer.prototype.toString'utf8' is called on a Buffer backed by a SharedArrayBuffer, the underlying native code performs a validate-then-convert sequence without copying the data...

curl: Heap-OOB read in urlapi `redirect_url()` via `CURLU_GUESS_SCHEME` + `CURLU_NO_GUESS_SCHEME` flow

Hi all, We've found an issue in lib/urlapi.c where redirecturl reads past the end of a heap buffer when the source URL it operates on lacks a "scheme://" prefix. This is reachable through documented public APIs curlurlset when the caller mixes CURLUGUESSSCHEME with a subsequent CURLUNOGUESSSCHEME...

curl: Use-after-free in `curl_easy_duphandle()` with HTTP/2 stream-dependency tree

Hi all, We've found an issue in lib/easy.c where curleasyduphandle shallow-copies set.priority, so the original and the duplicate end up holding two independent pointer-typed variables that both reference the same heap-allocated Curldataprionode chain. Freeing the chain from one side leaves the...

curl: curl cross-origin HTTPS redirect reuses TLS client certificate for unintended second-origin mTLS authentication

Summary: When curl follows an HTTPS redirect to a different origin under normal -L / CURLOPTFOLLOWLOCATION behavior, it still presents the configured TLS client certificate to the redirected-to HTTPS server. This happens without --location-trusted / CURLOPTUNRESTRICTEDAUTH, even though curl alrea...

curl: curl --skip-existing has a TOCTOU race that lets a post-check symlink redirect the later download write

Summary: The curl CLI's --skip-existing option performs a separate existence check before the download body is written. In the verified path, curl first calls stat on the target pathname and decides "the file does not exist, so continue", but it does not keep an fd bound to that decision. The...

Revive Adserver: PHP code injection via unexpected delivery limitation parameter

A vulnerability was reported in Revive Adserver 6.0.6 and earlier versions where user input was not properly validated when saving delivery limitations. This allowed a low-privileged user to inject malicious PHP code into the compiledlimitations field, which could then be executed during banner...

curl: CRLF Injection via Custom HTTP Headers

Summary: libcurl writes user-supplied custom headers directly into the HTTP request buffer without stripping \r\n characters. The raw input pointer origp in Curladdcustomheaders lib/http.c is serialized verbatim into the outgoing request using curlxdynaddfreq, "%s\r\n", origp instead of using the...

curl: Connection reuse ignores haproxyprotocol and HAPROXY_CLIENT_IP settings, allowing PROXY context to persist across transfers

Summary: libcurl's connection pool match logic does not include the CURLOPTHAPROXYPROTOCOL setting or the CURLOPTHAPROXYCLIENTIP value in its connection match key. Two transfers issued through the same Curleasy or via a shared connection cache CURLLOCKDATACONNECT therefore share one TCP connectio...

curl: SSL session-cache peer key omits signature_algorithms: strict-sigalg handle silently resumes a permissive sibling's session

CURLOPTSSLSIGNATUREALGORITHMS policy bypass: SSL session cache key omits sigalgs, allowing a strict-sigalg handle to resume a session negotiated under a permissive policy AI disclosure This report was prepared with the assistance of an AI coding assistant Claude. The behavioral diff pre/post patc...

AWS VDP: Firecracker Out-of-bounds Read/Write Local Privilege Escalation Vulnerability

A vulnerability was discovered in Firecracker versions up to 1.15.1 that could allow a malicious guest to bypass protection mechanisms and perform out-of-bounds read and write operations on the virtio PCI queue. The vulnerability was caused by inconsistencies in the handling of queue activation...

Node.js: NULL pointer dereference in node:sqlite DatabaseSync#applyChangeset() via malformed SQLite changeset

Summary: A 19-byte malformed SQLite changeset passed to Node.js node:sqlite DatabaseSyncapplyChangeset causes a native NULL pointer dereference and terminates the Node.js process. Description: The built-in Node.js node:sqlite API exposes DatabaseSyncapplyChangesetchangeset, options, which accepts...

curl: NULL pointer dereference in libcurl URL API redirect_url() with CURLU_DEFAULT_SCHEME

Summary A NULL pointer dereference appears to exist in libcurl's URL API path when curlurlset handles a relative URL together with CURLUDEFAULTSCHEME on a CURLU handle that has host/path information but no stored u-scheme. The issue is in lib/urlapi.c inside redirecturl, where u-scheme is used in...

curl: TLS peer-verification bypass via mid-transfer ssl_config mutation

Hi all, We want to report a TLS peer-verification issue on current master. The trigger is narrow and requires a specific application usage pattern, but when it fires, a transfer that requests CURLOPTSSLVERIFYPEER=1 can reuse a TLS connection that was established with peer verification disabled...

curl: cookie: case-insensitive path comparison in replace_existing() allows cookie eviction across distinct paths

Hi all, replaceexisting in lib/cookie.c compares cookie paths case-insensitively at two sites. On case-sensitive servers, /Admin and /admin are distinct resources and are supposed to produce distinct jar entries. Because libcurl conflates them, a Set-Cookie at one path silently evicts the cookie ...

curl: CURLOPT_PROXY_CAINFO_BLOB silently activates native CA store on Apple builds

Hi all, CURLOPTPROXYCAINFOBLOB introduced 7.77.0 never sets proxyssl.customcablob. On USEAPPLESECTRUST / CURLCANATIVE builds this causes curl to silently fall back to the system keychain for proxy TLS verification, nullifying the caller's blob-only trust policy. --- Root cause lib/setopt.c handle...

curl: libssh SFTP initialization ignores CURLOPT_TIMEOUT, hangs indefinitely

Hi all, The libssh backend in lib/vssh/libssh.c ignores CURLOPTTIMEOUT / --max-time during SFTP subsystem negotiation. A server that completes SSH authentication and then stalls before answering the SSHFXPINIT packet will pin the curl process indefinitely — no timeout fires, no error is returned,...

curl: Schannel custom-CA path skips Extended Key Usage enforcement

Hi all, We believe the Schannel custom-CA verification path in lib/vtls/schannelverify.c may skip Extended Key Usage enforcement. In particular, a certificate that chains to the trusted custom CA but contains only id-kp-clientAuth, rather than id-kp-serverAuth, may pass peer verification on Windo...

curl: HTTP/3 paused transfer buffers incoming data without bound up to ~1 GiB

Hi all, When a libcurl application's CURLOPTWRITEFUNCTION returns CURLWRITEFUNCPAUSE, libcurl routes subsequent incoming body data through cw-pause lib/cw-pause.c. The bufq inside cw-pause is initialised with BUFQOPTSOFTLIMIT and a chunk size of 16 KiB lib/cw-pause.c:51-52, which causes bufq to...

curl: rustls backend silently ignores CURLOPT_CRLFILE when native CA store is active

Hi all, When the rustls backend is configured to use the OS native CA store --ca-native / CURLSSLOPTNATIVECA, any CRL file supplied via --crlfile / CURLOPTCRLFILE is silently ignored. The option is accepted — CURLEOK from curleasysetopt, exit 0 from the command line — and revoked certificates pas...

curl: Trailing-dot IPv4 URL bypasses IP-address guard, allows wildcard DNS SAN match

Hi all, Sorry to ruin anybody's day, but we've discovered another issue when it comes to dots. We've found a TLS certificate verification bypass that lets a trailing-dot IPv4 URL -- https://127.0.0.1./ -- pass peer authentication against a wildcard DNS SAN certificate such as DNS:.0.0.1. The IP...

Rocket.Chat: Autotranslate DDP Method Exposes Private Messages Without Authentication or Room Access Check

Vulnerability description not provided...

curl: TLS verifyhost bypass in rustls, mbedTLS, and wolfSSL when verifypeer=0

The now-well-known CURLOPTSSLVERIFYHOST-bypass-when-CURLOPTSSLVERIFYPEER=0 defect exists in three of curl's TLS backends: rustls EXPERIMENTAL, mbedTLS, and wolfSSL DNS hostnames only. The documented contract at docs/libcurl/opts/CURLOPTSSLVERIFYPEER.md:57-59: The check that the host name in the...

curl: HTTP/2 proxy CONNECT tunnel unbounded 1xx chain (missing Curl_bump_headersize cap in cf-h2-proxy.c)

A malicious HTTPS-on-HTTP/2 proxy can grow a libcurl client's resident set without bound during the CONNECT phase by streaming 1xx informational responses. The CVE-2023-38039 cap MAXHTTPRESPHEADERSIZE, 300 KiB, enforced through Curlbumpheadersize is not applied on the HTTP/2 proxy path. The HTTP/...

curl: HSTS multi-trailing-dot bypass-ish: possible incomplete fix for CVE-2022-30115

Hi all, Honestly, I'm not completely certain about this issue, but I think the CVE-2022-30115 fix "HSTS bypass via trailing dot" is incomplete: the same asymmetry exists for hostnames with two or more trailing dots, so http://example.com../ still gets sent in plaintext when there's a valid HSTS...

curl: Credentials forwarded to HTTP after HTTPS→HTTP same-port redirect — url_set_data_creds uses scheme-blind comparator

Hi all, The recent creds: hold credentials refactor — commit 8f71d0fde5 2026-05-11 https://github.com/curl/curl/commit/8f71d0fde5 — introduced a credential-leak regression on HTTPS→HTTP same-port redirects. -u user:pass and --oauth2-bearer both end up in cleartext after a 302 from https://h:N/ to...