wrong proxy connection reuse with credentials

curl would wrongly reuse an existing HTTP proxy connection doing CONNECT to a server, even if the new request uses different credentials for the HTTP proxy. The proper behavior is to create or use a separate connection...

curl 安全漏洞

curl is an open-source tool developed by cURL for transferring data from or to a server. Curl has a security vulnerability that stems from a logical error leading to improper reuse of connections. This allows requests using different credentials to mistakenly reuse the same connection...

PT-2026-24661

Name of the Vulnerable Software and Affected Versions libcurl affected versions not specified Description libcurl may reuse an incorrect connection when handling Negotiate-authenticated HTTP or HTTPS requests. This occurs because libcurl maintains a pool of recent connections to avoid overhead. A...

Linux Distros Unpatched Vulnerability : CVE-2026-1965

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available. - 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 recen...

curl: Connection Reuse Ignores OAuth Bearer Token Mismatch

Summary: The connection pool reuse function urlmatchconn in lib/url.c checks oauthbearer in its credential match block — but only for protocols marked as requiring per-connection credentials. For HTTP, OAuth bearer is passed as a header, not a protocol-level credential. If a libcurl application...

curl: Use-After-Free in SMB connection reuse (req->path dangling pointer after needle destruction)

Summary A heap-use-after-free occurs in smbsendopen at lib/smb.c when curl processes two SMB URLs targeting the same host. The function smbparseurlpath sets req-path as a non-owning pointer into smbc-share connection-owned memory. During connection reuse, the needle connection is freed via...

curl: CVE-2026-3805: use after free in SMB connection reuse

Summary A heap-use-after-free occurs in smbsendopen at lib/smb.c when curl processes two SMB URLs targeting the same host. The function smbparseurlpath sets req-path as a non-owning pointer into smbc-share connection-owned memory. During connection reuse, the needle connection is freed via...

MiracleLinux 8 : curl-7.61.1-30.el8.2.ML.1 (AXSA:2023-6186:10)

The remote MiracleLinux 8 host has packages installed that are affected by a vulnerability as referenced in the AXSA:2023-6186:10 advisory. curl: FTP too eager connection reuse CVE-2023-27535 Tenable has extracted the preceding description block directly from the MiracleLinux security advisory...

MiracleLinux 8 : curl-7.61.1-22.el8.3 (AXSA:2022-3782:01)

The remote MiracleLinux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the AXSA:2022-3782:01 advisory. curl: OAUTH2 bearer bypass in connection re-use CVE-2022-22576 curl: credential leak on redirect CVE-2022-27774 curl: auth/cookie leak on redirect...

MiracleLinux 9 : curl-7.76.1-23.el9.1 (AXSA:2023-6065:09)

The remote MiracleLinux 9 host has packages installed that are affected by a vulnerability as referenced in the AXSA:2023-6065:09 advisory. curl: FTP too eager connection reuse CVE-2023-27535 Tenable has extracted the preceding description block directly from the MiracleLinux security advisory...

MiracleLinux 4 : curl-7.19.7-37.AXS4.3 (AXSA:2014-397:01)

The remote MiracleLinux 4 host has packages installed that are affected by multiple vulnerabilities as referenced in the AXSA:2014-397:01 advisory. cURL is a tool for getting files from HTTP, FTP, FILE, LDAP, LDAPS, DICT, TELNET and TFTP servers, using any of the supported protocols. cURL is...

curl: Cross‑Layer State Confusion in libcurl: Credential & Key‑Material Persistence Across Redirect / Connection Reuse Boundaries

Summary: This report describes a state‑level security invariant violation in libcurl where credential‑ or key‑related state may persist or be re‑applied across logical trust boundaries redirects, connection reuse, or scheme transitions without a formal invariant enforcing reset semantics. The iss...

curl: HAProxy Connection Reuse leads to IP Spoofing and mTLS Context Smuggling

Executive Summary libcurl fails to respect the CURLOPTHAPROXYCLIENTIP configuration when reusing existing connections. Due to a missing check in the connection pooling logic, libcurl indiscriminately reuses a TCP/TLS connection established with a specific identity IP A for subsequent requests...

Siemens SIMATIC S7-1500 Improper Authentication (CVE-2023-27536)

An authentication bypass vulnerability exists libcurl 8.0.0 in the connection reuse feature which can reuse previously established connections with incorrect user permissions due to a failure to check for changes in the CURLOPTGSSAPIDELEGATION option. This vulnerability affects...

Siemens SIMATIC S7-1500 Improper Input Validation (CVE-2023-27538)

libcurl would reuse a previously created connection even when an SSH related option had been changed that should have prohibited reuse. libcurl keeps previously used connections in a connection pool for subsequent transfers to reuse if one of them matches the setup. However, two SSH settings were...

Siemens SIMATIC S7-1500 Missing Encryption of Sensitive Data (CVE-2022-27775)

An information disclosure vulnerability exists in curl 7.65.0 to 7.82.0 are vulnerable that by using an IPv6 address that was in the connection pool but with a different zone id it could reuse a connection instead. This plugin only works with Tenable.ot. Please visit...

Siemens SIMATIC S7-1500 Improper Authentication (CVE-2023-27535)

An authentication bypass vulnerability exists in libcurl 8.0.0 in the FTP connection reuse feature that can result in wrong credentials being used during subsequent transfers. Previously created connections are kept in a connection pool for reuse if they match the current setup. However, certain...

Astra Linux – Vulnerability in curl

In some cases, curl may reuse the wrong connection for SMB transfers. curl features a pool of recent connections, so subsequent requests can reuse an existing connection to avoid additional overhead. When reusing a connection, a set of criteria must be met. Due to a logical error in the code, a...

JLSEC-2025-33 An authentication bypass vulnerability exists in libcurl prior to v8.0.0 where it reuses a...

An authentication bypass vulnerability exists in libcurl prior to v8.0.0 where it reuses a previously established SSH connection despite the fact that an SSH option was modified, which should have prevented reuse. libcurl maintains a pool of previously used connections to reuse them for subsequen...

JLSEC-2025-30 An authentication bypass vulnerability exists libcurl <8.0.0 in the connection reuse feature which...

An authentication bypass vulnerability exists libcurl 8.0.0 in the connection reuse feature which can reuse previously established connections with incorrect user permissions due to a failure to check for changes in the CURLOPTGSSAPIDELEGATION option. This vulnerability affects...