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.

Published 2026-07-03 · last modified 2026-09-15.

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.

EPSS exploit prediction

EPSS: 0.006 (47.3th percentile), scored 2026-10-04.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 47th percentile — 47.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000

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.