curl: Information disclosure due to uncleared proxy authentication state

A flaw was found in libcurl. When reusing a libcurl handle for sequential transfers with environment-variable proxy configuration, the library does not properly clear the proxy authentication state. This oversight can lead to the unintended disclosure of Proxy-Authorization headers to an incorrec...

libcurl: libcurl: Information disclosure due to persistent Referer header

A flaw was found in libcurl. This vulnerability causes the HTTP Referer header to persist even after it has been explicitly cleared. This can lead to the previous referrer string being unintentionally reused and sent in subsequent requests, potentially disclosing sensitive information to unintend...

Security Bulletin: Vulnerability impacts AIX due to cURL libcurl (CVE-2026-5545).

Summary A logic error allows libcurl to reuse an existing Negotiate-authenticated connection even when a new request specifies different credentials for the same server. Vulnerability Details CVEID:CVE-2026-5545 DESCRIPTION: libcurl might in some circumstances reuse the wrong connection when aske...

Multiple vulnerabilities impacts AIX due to cURL libcurl (CVE-2025-14819 CVE-2026-1965 CVE-2026-3783 CVE-2026-3784 CVE-2026-5545)

IBM SECURITY ADVISORY First Issued: Fri Jun 26 01:16:13 CDT 2026 The most recent version of this document is available here: https://aix.software.ibm.com/aix/efixes/security/curladvisory10.asc Security Bulletin: Multiple vulnerabilities impacts AIX due to cURL libcurl CVE-2025-14819, CVE-2026-196...

libcurl 7.69.0 < 8.21.0 SSH Improper Host Validation

The version of libcurl installed on the remote host is 7.69.0 prior to 8.21.0. It is, therefore, affected by an improper host validation vulnerability: - When a libcurl-based application performs transfers via SCP or SFTP and utilizes the CURLOPTSSHKEYFUNCTION callback, it may silently accept an...

libcurl 8.13.0 < 8.21.0 Use-After-Free in Socket Callback

The version of libcurl installed on the remote host is 8.13.0 prior to 8.21.0. It is, therefore, affected by a use-after-free vulnerability: - Calling curleasypause within the event-based CURLMOPTSOCKETFUNCTION callback triggers a use-after-free vulnerability. CVE-2026-9080 Note that Nessus has n...

libcurl 8.17.0 < 8.21.0 Native CA Trust Persist

The version of libcurl installed on the remote host is 8.17.0 prior to 8.21.0. It is, therefore, affected by an improper certificate validation vulnerability: - An easy handle that first uses default native CA trust can continue trusting the native platform store after the application switches th...

libcurl 7.7 < 8.21.0 Incomplete mTLS Config Matching in Connection Reuse

The version of libcurl installed on the remote host is 7.7 prior to 8.21.0. It is, therefore, affected by an improper certificate validation vulnerability: - libcurl would reuse a previously created connection even when some mTLS config related option had been changed that should have prohibited...

libcurl 7.88.0 < 8.21.0 HTTP/2 Stream-Dependency Tree Use-After-Free

The version of libcurl installed on the remote host is 7.88.0 prior to 8.21.0. It is, therefore, affected by a use-after-free vulnerability: - A use-after-free vulnerability exists in libcurl when an application configures an HTTP/2 stream-dependency tree and subsequently invokes curleasyreset...

libcurl 7.43.0 < 8.21.0 Wrong Negotiate Connection Reuse

The version of libcurl installed on the remote host is 7.43.0 prior to 8.21.0. It is, therefore, affected by an improper connection reuse vulnerability: - libcurl might in some circumstances reuse the wrong connection when asked to do Negotiate-authenticated ones, even when they are set to use...

libcurl 8.18.0 < 8.21.0 Persistent Referer Header Information Disclosure

The version of libcurl installed on the remote host is 8.18.0 prior to 8.21.0. It is, therefore, affected by an information disclosure vulnerability: - A vulnerability in libcurl caused the HTTP Referer header to persist even when explicitly cleared, potentially leaking sensitive information to...

libcurl 7.10.6 < 8.21.0 Cross-Origin Digest Auth State Leak

The version of libcurl installed on the remote host is 7.10.6 prior to 8.21.0. It is, therefore, affected by a credential disclosure vulnerability: - Successfully using libcurl with Digest authentication and then changing the origin to a different host for a second transfer, reusing the same...

libcurl 7.12.0 < 8.21.0 Cross-Proxy Digest Auth State Leak

The version of libcurl installed on the remote host is 7.12.0 prior to 8.21.0. It is, therefore, affected by a proxy credential disclosure vulnerability: - When reusing a libcurl handle for sequential transfers driven by environment-variable proxy configuration, libcurl fails to clear the proxy...

libcurl 8.8.0 < 8.21.0 Stale Proxy Password Leak

The version of libcurl installed on the remote host is 8.8.0 prior to 8.21.0. It is, therefore, affected by a credential disclosure vulnerability: - libcurl had a flaw that when instructed to clear proxy authentication credentials, it did not do so, leaving the old credentials around to get used...

ThreatsDay Bulletin: Smart TV Proxyware, 24-Year curl Bug, AI Crime Forums + 13 More Stories

It’s dumb out there again. This week has the usual smell of prod on fire and nobody wanting to admit who left the door open — old creds still working, trusted apps doing sketchy crap, browser tricks jumping the fence, and “normal” workflows turning into phishing pipes because apparently email was...

The vulnerability of the UDP packet reception function in QUIC’s libcurl library, a software library for interacting with servers via cURL, allows a attacker to cause a service failure.

The vulnerability of the UDP packet reception function in the QUIC library of the cURL software for interacting with servers is related to the execution of a loop with an unavailable exit condition. Exploiting this vulnerability could allow a remote attacker to cause service failures...

The vulnerability of the dependency management mechanism for HTTP/2 protocols in the libcurl library of the software tool for interacting with servers via cURL allows a attacker to cause a service failure.

The vulnerability of the dependency management mechanism for HTTP/2, as well as the libcurl library used in the cURL client software for interacting with servers, relates to the possibility of exploiting memory after it is freed. Exploiting this vulnerability could allow a remote attacker to caus...

Astra Linux – Vulnerability in curl

When performing SSH-based transfers using either SCP or SFTP, and setting the knownhosts file, libcurl may still mistakenly accept connections to hosts that are not present in the specified file, if those hosts are added as recognized in the libssh global knownhosts file...

CVE-2026-8927

When reusing a libcurl handle for sequential transfers driven by environment-variable proxy configuration, libcurl fails to clear the proxy authentication state between requests. Specifically, if the initial transfer authenticates against proxyA using Digest auth, a subsequent transfer routed...

UBUNTU-CVE-2026-9080

Calling curleasypause within the event-based CURLMOPTSOCKETFUNCTION callback triggers a use-after-free vulnerability, where libcurl attempts to store a flag using a dangling struct pointer immediately after that pointer's memory has been freed...