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: 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: 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: 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 --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: 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...

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...

curl: CURLOPT_HSTS_CTRL disables shared HSTS without share guard — use-after-free and double-free

Hi all, CURLOPTHSTSCTRL set to a value without CURLHSTSENABLE unconditionally frees the easy's HSTS object — even when that object is shared via a CURLSH. The result is a use-after-free and a double-free on the shared 48-byte struct hsts block when the share or any other linked easy is later torn...

curl: Kerberos/SPNEGO Connection Reuse Vulnerability

Kerberos/SPNEGO Connection Reuse Vulnerability in curl Summary curl reuses HTTP connections across different users without checking Kerberos state. User B's request can inherit User A's GSS security context, allowing authentication bypass. Affected Versions All curl versions with Kerberos support...

Liberapay: another liberapay member team twitter account broken Link Hijacking via Expired Twitter Account Link

Hello again i discovered that there is another Liberapay profile of Liberapay team member at liberapay.com/mdvhimself contains a link to an expired Twitter account, creating a Broken Link Hijacking BLH vulnerability. An attacker could register the expired handle and control what appears to be an...

Liberapay: Liberapay member team twitter account broken Link Hijacking via Expired Twitter Account Link

The profile of a Liberapay team member contained a link to an expired Twitter account, creating a broken link hijacking vulnerability. The expired Twitter account link was displayed on the member's Liberapay profile and donation page, falsely confirming to donors that the account was legitimate a...

curl: Shared HSTS cache accessed without lock

This is finding F5 in Andrew's report https://github.com/curl/curl/blob/455bebc2c7/lib/hsts.cL160-L168 https://github.com/curl/curl/blob/455bebc2c7/lib/http.cL3571 https://github.com/curl/curl/blob/455bebc2c7/lib/url.cL1441 https://github.com/curl/curl/blob/455bebc2c7/lib/url.cL265...

curl: CURLOPT_PROXY_CRLFILE / CURLOPT_PROXY_ISSUERCERT / CURLOPT_PROXY_ISSUERCERT_BLOB silently ignored on backends that don't support them

From the Mythos report 2026-05-06 F1. CURLOPTPROXYCRLFILE / CURLOPTPROXYISSUERCERT / CURLOPTPROXYISSUERCERTBLOB silently ignored on backends that don't support them — severity Low https://github.com/curl/curl/blob/455bebc2c7/lib/setopt.cL1786-L1797...

curl: mbedTLS private-key blob null-termination asymmetry in lib/vtls/mbedtls.c (mbed_load_privkey)

Summary: In lib/vtls/mbedtls.c, function mbedloadprivkey lines 653-738 passes raw sslkeyblob-data and sslkeyblob-len directly to mbedtlspkparsekey at lines 706-708 mbedTLS 4.x branch and 718-722 mbedTLS 3.x branch, without ensuring null-termination. The mbedTLS API contract for mbedtlspkparsekey...

Rocket.Chat: IDOR: autotranslate.translateMessage Full Message Content Leak

The /api/v1/autotranslate.translateMessage endpoint allowed any authenticated user to retrieve the full content of any message from any room, including private groups, direct messages, and channels. The endpoint fetched the message without performing a room access check, returning the complete...

curl: MQTT CONNACK Packet Type Bypass leads to RCE via Malicious Broker

Summary: mqttverifyconnack in lib/mqtt.c never checks that the received packet type is actually a CONNACK 0x20. The constant MQTTMSGCONNACK is commented out at line 45, making the check impossible to write. A malicious broker can send any packet — e.g. PUBACK 0x40 — with remaininglength=2 and...

curl: Potential Resource Leak in tool_parsecfg.c at line 279 during fileerror

Summary: A resource leak was identified in src/toolparsecfg.c using the Clang Static Analyzer. When a file error occurs fileerror is true during config parsing, the function returns PARAMREADERROR without ensuring the file stream is properly closed, leading to a potential file descriptor leak...

curl: wcurl treats some URL operands after -- as curl options

I found that wcurl does not always keep operands after -- in a pure URL-data context. The documented way to pass curl options through wcurl is --curl-options, but a value supplied as a URL operand can still reach the final curl command as an option, for example wcurl -- "--url=file:///...". A...

curl: libcurl 8.20.0 incomplete fix for CVE-2026-7168: changing only CURLOPT_PROXYPORT leaks stale Proxy Digest auth to a different proxy

Summary: I found an incomplete-fix variant of CVE-2026-7168 in curl 8.20.0. The 8.20.0 fix clears state.proxydigest / state.authproxy when CURLOPTPROXY changes, but not when only CURLOPTPROXYPORT changes. On the same easy handle, request 1 through proxyA CURLOPTPROXYPORT=18197 learns Proxy Digest...

curl: MQTT state machine confusion: PINGRESP/DISCONNECT with non-zero remaining_length dispatches to stale nextstate

Summary: In lib/mqtt.c, the state machine in mqttdoing lines 894-911 in curl 8.20.0 does not validate that PINGRESP 0xD0 and DISCONNECT 0xE0 packets have remaininglength == 0 as required by MQTT 3.1.1 spec sections 3.13.1 and 3.14.1. A malicious broker can send a PINGRESP fixed header with non-ze...