Vulnerability in Curl
CVE-2026-11564
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.
Vulnerability class: Improper Certificate Validation
EPSS: 0.004 (29.0th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.
Affected products
Weakness classification (CWE)
References
- 2499f714-1537-4658-8207-48ae4bb9eae9 (Vendor Advisory)
- 2499f714-1537-4658-8207-48ae4bb9eae9 (Patch, Vendor Advisory)
- 2499f714-1537-4658-8207-48ae4bb9eae9 (Exploit, Third Party Advisory, Issue Tracking)
Frequently asked questions
- What is CVE-2026-11564?
- CVE-2026-11564 is a critical-severity vulnerability in Curl, classified under Improper Certificate Validation. CVSS score: 9.1/10. Published 2026-07-03.
- How severe is CVE-2026-11564?
- Critical severity. CVSS v3 base score is 9.1 out of 10.