CURL-CVE-2026-7168 cross-proxy Digest auth state leak

Successfully using libcurl to do a transfer over a specific HTTP proxy proxyA with Digest authentication and then changing the proxy host to a second one proxyB for a second transfer, reusing the same handle, makes libcurl wrongly pass on the Proxy-Authorization: header field meant for proxyA, to...

PT-2026-35895

Name of the Vulnerable Software and Affected Versions curl affected versions not specified Description When using libcurl, a flaw exists where a custom Host: header set for an initial HTTP request can cause subsequent requests using the same easy handle to use stale information. If the second...

PT-2026-35893

Name of the Vulnerable Software and Affected Versions libcurl affected versions not specified Description A logical error in the connection pooling mechanism may cause libcurl to reuse an incorrect connection for SMBS transfers. When reusing a connection, specific criteria must be met; however, a...

Insertion of Sensitive Information Into Sent Data

Overview Affected versions of this package are vulnerable to Insertion of Sensitive Information Into Sent Data via the reuse of a proxy connection during HTTP redirects when using .netrc for credentials. An attacker can obtain sensitive credential information by intercepting traffic if both the...

curl: CVE-2026-7168: cross-proxy Digest auth state leak

Summary: On libcurl 8.19.0, Proxy Digest state learned from proxyA survives an independent transfer boundary on a reused easy handle and is emitted preemptively to proxyB when the proxy is changed. In the attached C PoC, the first CONNECT to proxyB carries Proxy-Authorization: Digest ... built fr...

curl: libcurl reuses a learned RTSP Session header across different hosts on the same easy handle, enabling cross-host session leak and replay

Summary: libcurl automatically learns RTSP Session: headers from server responses and stores them in data-set.strSTRINGRTSPSESSIONID in lib/rtsp.c:1015-1033. On later RTSP requests using the same easy handle, rtspdo reads that easy-handle-scoped value at lib/rtsp.c:373 and unconditionally emits...

curl: libssh key passphrase bypass without agent set

A flaw was found in libcurl. When doing SSH-based transfers using either SCP or SFTP, and asked to do public key authentication, curl would wrongly still ask and authenticate using a locally running SSH agent...

Moderate: Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update

An update for Red Hat Hardened Images RPMs is now available. This update includes the following RPMs: curl: curl-8.19.0-3.hum1 aarch64, x8664 libcurl-8.19.0-3.hum1 aarch64, x8664 libcurl-devel-8.19.0-3.hum1 aarch64, x8664 libcurl-minimal-8.19.0-3.hum1 aarch64, x8664 curl-8.19.0-3.hum1.src source...

curl: libcurl: Improper certificate validation due to cached TLS settings reuse

A flaw was found in libcurl. When handling secure connections TLS and reusing connection settings, libcurl could incorrectly apply a cached security setting related to certificate chain validation. This could allow libcurl to accept a server's security certificate that it should have otherwise...

CVE-2026-33752 Redirect-based SSRF leading to internal network access in curl_cffi (with TLS impersonation bypass)

curlcffi is the a Python binding for curl. Prior to 0.15.0, curlcffi does not restrict requests to internal IP ranges, and follows redirects automatically via the underlying libcurl. Because of this, an attacker-controlled URL can redirect requests to internal services such as cloud metadata...

curl_cffi: Redirect-based SSRF leads to internal network access in curl_cffi (with TLS impersonation bypass)

Summary curlcffi does not restrict requests to internal IP ranges, and follows redirects automatically via the underlying libcurl. Because of this, an attacker-controlled URL can redirect requests to internal services such as cloud metadata endpoints. In addition, curlcffi’s TLS impersonation...

curl: ignoring 'options' when doing connection reuse

libcurl contains a significant logic flaw in its connection pool matching mechanism. When a transfer specifies a required authentication policy—such as a specific SASL mechanism e.g., ;AUTH=GSSAPI or a restricted set of SSH authentication types CURLOPTSSHAUTHTYPES—libcurl fails to verify these...

curl: # SCURLOPT_SSH_KNOWNHOSTS and host fingerprint pins are silently bypassed when an SSH connection is reused from the connection pool

Product libcurl all versions, all platforms, compiled with USESSH Protocols affected: sftp://, scp:// --- Summary libcurl's connection pool reuse logic for SSH-based protocols SFTP, SCP contains a security gap that allows a transfer's server-verification policy to be completely ignored. When an...

curl: Bypassing Strict SSH Server Verification via Connection Pool Reuse in libcurl

Summary There is a logic flaw in how libcurl manages its connection pool for SSH protocols SFTP/SCP. When evaluating an existing connection for reuse, sshconfigmatches in lib/url.c fails to compare server identity verification policies. By ignoring CURLOPTSSHKNOWNHOSTS, CURLOPTSSHHOSTPUBLICKEYMD5...

curl: Use-After-Free race condition in url_move_hostname() via shared connection pool

Summary: In lib/url.c, urlconnreuseadjust calls urlmovehostname which frees conn-host.rawalloc and conn-host.encalloc via Curlsafefree and Curlfreeidnconvertedhostname after Curlcpoolfind has already released the connection pool lock. A second thread doing a concurrent pool lookup still holds tha...

curl: HackerOne Vulnerability Report: libcurl SSL/TLS Identity Leakage via Insecure Connection Reuse

Summary libcurl contains a critical logic flaw in its connection reuse mechanism where transfers using the CURLOPTSSLCTXFUNCTION SSL context callback to establish a specific identity e.g., via client certificates can have their connections incorrectly reused by subsequent, unauthenticated transfe...

curl: Unbounded GZIP Decompression Leading to Event-Loop Starvation

When libcurl is configured to decompress HTTP responses via CURLOPTACCEPTENCODING or the --compressed CLI flag, it lacks decompression bounds checking or a mechanism to yield execution during massive expansion tasks. If an attacker provides a highly compressed payload zip bomb, libcurl's underlyi...

Curl 7.10.6 < 8.19.0 Authentication Bypass

The version of curl installed on the remote host is 7.10.6 prior to 8.19.0. It is, therefore, affected by an authentication bypass vulnerability: - libcurl can in some circumstances reuse the wrong connection when asked to do an Negotiate-authenticated HTTP or HTTPS request. libcurl features a po...

UBUNTU-CVE-2026-1965

libcurl can in some circumstances reuse the wrong connection when asked to do an Negotiate-authenticated HTTP or HTTPS request. libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection to avoid overhead. When reusing a connection a range of...

CVE-2026-1965

libcurl can in some circumstances reuse the wrong connection when asked to do an Negotiate-authenticated HTTP or HTTPS request. libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection to avoid overhead. When reusing a connection a range of...