curl: libcurl: Authentication bypass due to incorrect HTTP Negotiate connection reuse

A flaw was found in libcurl. An application using libcurl that performs an authenticated HTTPS request after a Negotiate-authenticated one to the same host may incorrectly reuse the previous connection. This authentication bypass vulnerability allows the second request to be sent over a connectio...

curl: curl: Information disclosure due to incorrect TLS connection reuse

A flaw was found in curl. A remote attacker could exploit this by initiating an unencrypted connection via IMAP, SMTP, or POP3 and then making a subsequent request to the same host that requires Transport Layer Security TLS. Due to incorrect connection reuse, the subsequent request would bypass t...

Curl 7.10.6 < 8.20.0 Wrong Reuse of HTTP Negotiate Connection

The version of curl installed on the remote host is 7.10.6 prior to 8.20.0. It is, therefore, affected by an authentication bypass vulnerability: - libcurl might in some circumstances reuse the wrong connection when asked to do an authenticated HTTPS request after a Negotiate-authenticated one,...

Curl 7.40.0 < 8.20.0 Wrong SMB Connection Reuse

The version of curl installed on the remote host is 7.40.0 prior to 8.20.0. It is, therefore, affected by a wrong SMB connection reuse vulnerability: - libcurl might in some circumstances reuse the wrong connection for SMBS transfers. The code erroneously did not consider the share name as a...

CVE-2026-5545

A flaw was found in libcurl. An application using libcurl that performs an authenticated HTTPS request after a Negotiate-authenticated one to the same host may incorrectly reuse the previous connection. This authentication bypass vulnerability allows the second request to be sent over a connectio...

CVE-2026-4873

A flaw was found in curl. A remote attacker could exploit this by initiating an unencrypted connection via IMAP, SMTP, or POP3 and then making a subsequent request to the same host that requires Transport Layer Security TLS. Due to incorrect connection reuse, the subsequent request would bypass t...

CVE-2026-5773

libcurl might in some circumstances reuse the wrong connection for SMBS transfers. 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 criteria must be met. Due to a logical error in the...

CVE-2026-5545

libcurl might in some circumstances reuse the wrong connection when asked to do an authenticated HTTPS request after a Negotiate-authenticated one, when both use the same host. libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection to avoid...

UBUNTU-CVE-2026-5545

libcurl might in some circumstances reuse the wrong connection when asked to do an authenticated HTTPS request after a Negotiate-authenticated one, when both use the same host. libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection to avoid...

CURL-CVE-2026-5773 wrong reuse of SMB connection

libcurl might in some circumstances reuse the wrong connection for SMBS transfers. 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 criteria must be met. Due to a logical error in the...

CURL-CVE-2026-5545 wrong reuse of HTTP Negotiate connection

libcurl might in some circumstances reuse the wrong connection when asked to do an authenticated HTTPS request after a Negotiate-authenticated one, when both use the same host. libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection to avoid...

wrong reuse of SMB connection

libcurl might in some circumstances reuse the wrong connection for SMBS transfers. 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 criteria must be met. Due to a logical error in the...

wrong reuse of HTTP Negotiate connection

libcurl might in some circumstances reuse the wrong connection when asked to do an authenticated HTTPS request after a Negotiate-authenticated one, when both use the same host. libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection to avoid...

connection reuse ignores TLS requirement

A vulnerability exists where a connection requiring TLS incorrectly reuses an existing unencrypted connection from the same connection pool. If an initial transfer is made in clear-text via IMAP, SMTP, or POP3, a subsequent request to that same host bypasses the TLS requirement and instead transm...

Authentication Bypass by Primary Weakness

Overview Affected versions of this package are vulnerable to Authentication Bypass by Primary Weakness via the reuse of HTTP Negotiate authenticated connections. An attacker can gain unauthorized access or perform actions with unintended credentials by making an authenticated HTTPS request after ...

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...

PT-2026-35892

Name of the Vulnerable Software and Affected Versions libcurl affected versions not specified Description A logical error in the connection pooling mechanism allows libcurl to reuse an incorrect connection during authenticated HTTPS requests to the same host. If an application first performs a...

Cleartext Transmission of Sensitive Information

Overview Affected versions of this package are vulnerable to Cleartext Transmission of Sensitive Information due to the incorrect reuse of an unencrypted connection for a subsequent request that expects TLS. An attacker can intercept sensitive information if the second connection is done to the...

Exposure of Data Element to Wrong Session

Overview Affected versions of this package are vulnerable to Exposure of Data Element to Wrong Session due to the SMB connection reuse. An attacker can cause unintended file downloads or uploads to incorrect locations by exploiting a logical error in the reuse of SMB connections. Remediation...

Fedora 43 : curl (2026-66db242036)

The remote Fedora 43 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-66db242036 advisory. - Fix bad reuse of HTTP Negotiate connection CVE-2026-1965 - Fix token leak with redirect and netrc CVE-2026-3783 - Fix wrong proxy connection reuse...