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CVE-2026-11586

Haxx Curl denial of service

7.5 HIGHPublic exploitEPSS 0.61%
  1. Published3 Jul 2026

Description

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.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

Haxx Curl≥ 8.16.0 < 8.21.0

Remediation

Fixed in
Haxx Curl≥ 8.21.0

References

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Frequently asked

Is CVE-2026-11586 being actively exploited?

CVE-2026-11586 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.61%.

How severe is CVE-2026-11586?

CVE-2026-11586 has a CVSS 3.1 base score of 7.5, rated high. EPSS estimates a 0.61% probability of exploitation.

Which products are affected by CVE-2026-11586?

Affected products include Haxx Curl.

How do I fix CVE-2026-11586?

Upgrade affected software to a fixed version, for example Haxx Curl 8.21.0 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-11586 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.