Authentication Bypass Affecting curl package, versions <8.18.0-1ubuntu2.4


Severity

Recommended
medium

Based on Ubuntu security rating.

Threat Intelligence

EPSS
0.69% (51st percentile)

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  • Snyk IDSNYK-UBUNTU2604-CURL-17486821
  • published25 Jun 2026
  • disclosed3 Jul 2026

Introduced: 25 Jun 2026

CVE-2026-11856  (opens in a new tab)
CWE-294  (opens in a new tab)

How to fix?

Upgrade Ubuntu:26.04 curl to version 8.18.0-1ubuntu2.4 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream curl package and not the curl package as distributed by Ubuntu. See How to fix? for Ubuntu:26.04 relevant fixed versions and status.

Successfully using libcurl to do a transfer to a specific HTTP origin (hostA) with Digest authentication and then changing the origin to a different one (hostB) for a second transfer, reusing the same handle, makes libcurl wrongly pass on the Authorization: header field meant for hostA, to hostB.

CVSS Base Scores

version 3.1