Vulnerability · Published Jul 3, 2026 · Assigned by curl

CVE-2026-11564Native CA trust persist

Critical 9.1

In plain English

A critical-severity improper certificate validation in curl from curl. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 49% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)9.1Critical
Exploit odds (30 days)0.6%top 50.6% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official description

libcurl keeps previously used connections in a connection pool for subsequent transfers to reuse if one of them matches the setup. An easy handle that first uses default native CA trust can continue trusting the native platform store after the application switches that same handle to custom CA material for a later transfer.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Alpine:v3.23curl8.22.0-r0ALPINE-CVE-2026-11564
Alpine:v3.24curl8.21.0-r0ALPINE-CVE-2026-11564
Debian:14curl8.21.0~rc2-1DEBIAN-CVE-2026-11564
Ubuntu:26.04:LTScurl8.18.0-1ubuntu2.3UBUNTU-CVE-2026-11564

Affected products (as reported)

VendorProductVersions
curl curl 8.17.0 – before 8.20.1
curl curl eefd03c572996e5de4dec4fe295ad6f103e0eefc – before d69bfad3fa3daf5e72331f6870667607828d5891
curl curl 8.20.08.19.08.18.08.17.0

Weakness: CWE-295 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

References