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CVE-2026-19931

Negotiate ambient user conn reuse

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 8.14.2, 8.16.1, 8.20.1, 8.22.0
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: poc
  • Automatable: yes
  • Technical impact: total

Summary

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.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: poc · Automatable: yes · Technical impact: total

  3. Record last updated

Affected versions

  • curl curl

    From 7.64.1 · fixed in 8.14.2; From 8.15.0 · fixed in 8.16.1; From 8.17.0 · fixed in 8.20.1; From 8.21.0 · fixed in 8.22.0

  • curl curl

    Version range not reported

  • curl curl

    8.21.0, 8.20.0, 8.19.0, 8.18.0, 8.17.0, 8.16.0, 8.15.0, 8.14.1, 8.14.0, 8.13.0, 8.12.1, 8.12.0, 8.11.1, 8.11.0, 8.10.1, 8.10.0, 8.9.1, 8.9.0, 8.8.0, 8.7.1, 8.7.0, 8.6.0, 8.5.0, 8.4.0, 8.3.0, 8.2.1, 8.2.0, 8.1.2, 8.1.1, 8.1.0, and 36 more

References 3

curl.se

hackerone.com