What is CVE-2026-11586?

CVE-2026-11586 is a high-severity vulnerability in Curl, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 7.5/10. Published 2026-07-03.

How severe is CVE-2026-11586?

High severity. CVSS v3 base score is 7.5 out of 10.

Resource exhaustion in Curl

CVE-2026-11586

By default, curl automatically responds to WebSocket PING frames. Because curl lacks an upper bound on memory allocation for unacknowledged frames, a malicious server can exhaust all available memory by flooding curl with rapid, sequential PING messages.

EPSS: 0.005 (39.4th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Curl — versions 8.20.0, 8.19.0, 8.18.0
Haxx Curl

Weakness classification (CWE)

CWE-770 — Allocation of Resources Without Limits or Throttling

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-2026-11586?: CVE-2026-11586 is a high-severity vulnerability in Curl, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 7.5/10. Published 2026-07-03.
How severe is CVE-2026-11586?: High severity. CVSS v3 base score is 7.5 out of 10.