CVE-2026-11856 Affecting curl package, versions <8.21.0~rc3-1


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.6% (46th percentile)

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  • Snyk IDSNYK-DEBIANUNSTABLE-CURL-17440276
  • published24 Jun 2026
  • disclosed3 Jul 2026

Introduced: 24 Jun 2026

CVE-2026-11856  (opens in a new tab)

How to fix?

Upgrade Debian:unstable curl to version 8.21.0~rc3-1 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 Debian. See How to fix? for Debian:unstable 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