When asking curl to use a `.netrc` file to find credentials and at the same time specifying a URL with a username(without a password), like `https://user@example.com/`, curl could wrongly get and use the password for *another* user set in the `.netrc` file for that host if such a one exists and there is no match for the specified user.

The version of libcurl installed on the remote host is 8.11.1 prior to 8.21.0. It is, therefore, affected by a credential leak vulnerability:

  - When asking curl to use a .netrc file to find credentials and at the same time specifying a URL with a     username (without a password), curl could wrongly get and use the password for another user set in the     .netrc file for that host if such a one exists and there is no match for the specified user.
    (CVE-2026-8926)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 25.10 / 26.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-8487-1 advisory.

    Andrew Nesbitt discovered that curl could reuse an existing live connection during STARTTLS-based     connection upgrades even when the TLS configuration did not match. A remote attacker could possibly use     this issue to cause curl to use an unintended TLS configuration. (CVE-2026-8286)

    Muhamad Arga Reksapati discovered that curl incorrectly reused connections for Negotiate-authenticated     requests when different services were involved. A remote attacker could possibly use this issue to access     resources authenticated for another service. This issue only affected Ubuntu 18.04 LTS, Ubuntu 20.04 LTS,     Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, Ubuntu 25.10, and Ubuntu 26.04 LTS. (CVE-2026-8458)

    It was discovered that curl incorrectly handled cookie parsing in certain circumstances. A remote attacker     could possibly use this issue to set cookies that would be transmitted to unrelated third-party domains.
    This issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu     24.04 LTS, Ubuntu 25.10, and Ubuntu 26.04 LTS. (CVE-2026-8924)

    Joshua Rogers discovered that curl could double-free a GSASL context when handling SASL authentication. A     remote attacker could possibly use this issue to cause a denial of service, or execute arbitrary code.
    This issue only affected Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, Ubuntu 25.10, and Ubuntu 26.04 LTS.
    (CVE-2026-8925)

    Joshua Rogers discovered that curl could select the wrong password from a .netrc file when a username was     specified in the URL without a password. A remote attacker could possibly use this issue to obtain     sensitive information. This issue only affected Ubuntu 25.10 and Ubuntu 26.04 LTS. (CVE-2026-8926)

    Ady Elouej discovered that curl did not clear proxy authentication state between requests when reusing a     handle with environment-variable proxy configuration. A remote attacker could possibly use this issue to     obtain sensitive credentials. (CVE-2026-8927)

    Guannan Wang, Zhanpeng Liu, Jiashuo Liang, and Guancheng Li discovered that curl did not properly clear     proxy authentication credentials when instructed to do so. A remote attacker could possibly use this issue     to obtain sensitive credentials. This issue only affected Ubuntu 25.10 and Ubuntu 26.04 LTS.
    (CVE-2026-9079)

    Joshua Rogers discovered that curl contained a use-after-free when curl_easy_pause() was called within the     event-based socket callback. A remote attacker could possibly use this issue to cause a denial of service     or possibly execute arbitrary code. This issue only affected Ubuntu 25.10 and Ubuntu 26.04 LTS.
    (CVE-2026-9080)

    Eunsoo Kim discovered that curl could send early data on a resumed TLS session before enforcing     certificate verification failure. A machine-in-the-middle attacker could possibly use this issue to obtain     sensitive information. This issue only affected Ubuntu 25.10 and Ubuntu 26.04 LTS. (CVE-2026-9545)

    Joshua Rogers discovered that curl did not properly reject host key type mismatches when using the SSH key     callback for SCP and SFTP transfers. A machine-in-the-middle attacker could possibly use this issue to     impersonate a trusted server. This issue only affected Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, Ubuntu 25.10,     and Ubuntu 26.04 LTS. (CVE-2026-9547)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The version of curl installed on the remote host is 8.11.1 prior to 8.21.0. It is, therefore, affected by a credential disclosure vulnerability:

  - When asking curl to use a .netrc file to find credentials and at the same time specifying a URL with a     username, curl could wrongly get and use the password for another user set in the .netrc file.
    (CVE-2026-8926)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

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

  - When asking curl to use a `.netrc` file to find credentials and at the same time specifying a URL with a     username(without a password), like `https://user@example.com/`, curl could wrongly get and use the     password for *another* user set in the `.netrc` file for that host if such a one exists and there is no     match for the specified user. (CVE-2026-8926)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Severity
326235	libcurl 8.11.1 < 8.21.0 Netrc Wrong User Password Leak (CVE-2026-8926)	Nessus	Misc.	critical
324983	Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 25.10 / 26.04 LTS : curl vulnerabilities (USN-8487-1)	Nessus	Ubuntu Local Security Checks	critical
323004	Curl 8.11.1 < 8.21.0 Netrc Password Leak	Nessus	Misc.	critical
322432	Linux Distros Unpatched Vulnerability : CVE-2026-8926	Nessus	Misc.	critical

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CVE-2026-8926

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