CVE-2026-19931

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    CVE-2026-19931

    Published: 6 Sept 2026Last Modified: 17 Sept 2026

    Summary: Negotiate ambient user conn reuse

    Details: A flaw in libcurl makes it wrongly reuse an HTTP connection setup for a given hostname using Negotiate authentication, when the initial request is done using empty credentials. This can make user B's request get sent over user A's previously authenticated connection.

    References: https://curl.se/docs/CVE-2026-19931.html, https://curl.se/docs/CVE-2026-19931.json, https://hackerone.com/reports/3923520, https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/19xxx/CVE-2026-19931.json, https://nvd.nist.gov/vuln/detail/CVE-2026-19931, https://github.com/curl/curl.git

    Affected packages

    Package

    Name:

    Purl:

    Affected ranges

    Type: GIT

    Events:

    Introduced- 521bbbe29928f9bc1c61306df612e856d45cbe5a
    Fixed -01346829096c61b372692f6dc43ffa778c6caccd

    Affected versions

    7.64.1

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High
    CVE-2026-19931 | CVE-DB