curl: curl: Unauthorized access due to improper HTTP proxy connection reuse

A flaw was found in curl. This vulnerability allows curl to wrongly reuse an existing HTTP proxy connection when performing a CONNECT request to a server, even if the new request uses different authentication credentials for the HTTP proxy. This improper connection reuse could lead to an attacker...

curl: curl: Insecure connection establishment due to TLS configuration mismatch

A flaw was found in curl. When a new data transfer attempts to upgrade its connection using STARTTLS, it may incorrectly reuse an existing live connection. This reuse can occur even if the Transport Layer Security TLS configuration of the new transfer does not match the existing connection,...

curl: curl: Man-in-the-middle attack via SSH host key bypass

A flaw was found in curl. When a libcurl-based application uses SCP:// or SFTP:// for transfers and employs the CURLOPTSSHKEYFUNCTION callback, it may silently accept an untrusted server. This occurs if the server's host key type differs from the one stored in the knownhosts file. The callback...

curl: curl: Authentication bypass due to incorrect connection reuse with Negotiate authentication

A flaw was found in curl. When an application uses libcurl to make multiple Negotiate-authenticated HTTP or HTTPS requests to the same server with different credentials, libcurl may incorrectly reuse an existing connection. This logical error can cause a subsequent request to be sent using the...

curl: curl: Information disclosure via incorrect .netrc password lookup

A flaw was found in curl. When curl is configured to use a .netrc file for credentials and a URL is provided with a username but no password, curl may incorrectly retrieve and use the password for a different user from the .netrc file for the same host. This could lead to unauthorized information...

curl: curl: SSH host verification bypass when using schemeless URLs with SFTP/SCP

A flaw was found in curl. When a user invokes curl with a schemeless URL and specifies SFTP SSH File Transfer Protocol or SCP Secure Copy Protocol as the default protocol, the tool layer fails to initialize critical SSH security options. This bypasses host verification, allowing curl to connect t...

curl: curl: Cookie injection via malicious HTTP server using super cookies

A flaw was found in curl's cookie parsing logic. A malicious HTTP server can exploit this by setting 'super cookies' that bypass the Public Suffix List check. This allows an attacker-controlled origin to inject cookies that curl then transmits to unrelated third-party domains, leading to...

Important: Red Hat Security Advisory: curl security update

An update for curl is now available for Red Hat Enterprise Linux 10.0 Extended Update Support. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System CVSS base score, which gives a detailed severity rating, is available for...

curl: curl: Information disclosure via incorrect Digest authentication header reuse

A flaw was found in curl. When libcurl performs a transfer to an HTTP origin using Digest authentication and then reuses the same connection handle for a subsequent transfer to a different origin, it may incorrectly send the authentication header intended for the first origin to the second. This...

Important: curl

Issue Overview: When a user invokes curl using a schemeless URL combined with --proto-default sftp or scp, a disconnect occurs between the tool layer and libcurl. The tool layer incorrectly infers the URL scheme, which erroneously bypasses the initialization of critical SSH security options like...

curl: curl tool: --hsts is ignored for a schemeless URL starting with a slash under --proto-default http

Summary When the curl tool gets --proto-default http and a URL without a scheme that starts with a slash, such as /example.com/path, it skips all the options set in httpsetopts: --hsts, --alt-svc, the cookie options, -L and the rest. libcurl still performs the transfer, over plain HTTP. Unless an...

OESA-2026-4126 curl security update

cURL is a computer software project providing a library libcurl and command-line tool curl for transferring data using various protocols. Security Fixes: Successfully using libcurl to do a transfer to a specific HTTP origin hostA with Digest authentication and then changing the origin to a...

OESA-2026-4127 curl security update

cURL is a computer software project providing a library libcurl and command-line tool curl for transferring data using various protocols. Security Fixes: Successfully using libcurl to do a transfer to a specific HTTP origin hostA with Digest authentication and then changing the origin to a...

OESA-2026-4128 curl security update

cURL is a computer software project providing a library libcurl and command-line tool curl for transferring data using various protocols. Security Fixes: Successfully using libcurl to do a transfer to a specific HTTP origin hostA with Digest authentication and then changing the origin to a...

OESA-2026-4124 curl security update

cURL is a computer software project providing a library libcurl and command-line tool curl for transferring data using various protocols. Security Fixes: Successfully using libcurl to do a transfer to a specific HTTP origin hostA with Digest authentication and then changing the origin to a...

OESA-2026-4125 curl security update

cURL is a computer software project providing a library libcurl and command-line tool curl for transferring data using various protocols. Security Fixes: Successfully using libcurl to do a transfer to a specific HTTP origin hostA with Digest authentication and then changing the origin to a...

Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 26.04 LTS : curl vulnerabilities (USN-8820-1)

The remote Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 26.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-8820-1 advisory. Eunsoo Kim discovered that curl incorrectly handled SASL negotiation for LDAP authentication ...

curl: [HIGH] CWE-22 — Path Traversal in FTP Wildcard Download via Unencoded `.` in Escaped Filenames

Summary A malicious or MITM'd FTP server can cause a client using CURLOPTWILDCARDMATCH to download files outside the intended remote directory, by returning a LIST response with a filename containing .. path-traversal sequences. Details In the CURLWCDOWNLOADING state lib/ftp.c:4079-4095, each...

USN-8820-1 curl vulnerabilities

Eunsoo Kim discovered that curl incorrectly handled SASL negotiation for LDAP authentication in certain circumstances. A machine-in-the-middle attacker could possibly use this issue to bypass peer validation. This issue only affected Ubuntu 24.04 LTS and Ubuntu 26.04 LTS. CVE-2026-13608 Stephan...

USN-8820-1: curl vulnerabilities

Eunsoo Kim discovered that curl incorrectly handled SASL negotiation for LDAP authentication in certain circumstances. A machine-in-the-middle attacker could possibly use this issue to bypass peer validation. This issue only affected Ubuntu 24.04 LTS and Ubuntu 26.04 LTS. CVE-2026-13608 Stephan...