November 15, 2026

CVE Watchtower

CVE-2026-11586Haxx Curl Allocation of Resources Without Limits or Throttling

NVDCVSS scored by 134c704f-9b21-4f2e-91b3-4a467353bcc0

Vulnerability Summary

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.
Severity Level
HIGH(7.5)
Published Date
Jul 3, 2026
Last Modified
Jul 7, 2026
Exploitation Status
Public exploit available
EPSS Score (30-Day)
0.49%Probability
Root Weakness (CWE)
CWE-770: Allocation of Resources Without Limits or Throttling β†—
The product allocates a reusable resource on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated.
CVSS v3.1 Base Metrics — Score 7.5 (HIGH)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged
ConfidentialityNone
IntegrityNone
AvailabilityHigh

Affected & Patched Versions

Affected Versions
  • Haxx Curl >= 8.16.0 and < 8.21.0
Patched Versions
  • Haxx Curl 8.21.0

What to do

Prioritize this fix. Exploit code is public, so attacks can follow quickly.

  1. Check whether you run Haxx Curl and which version.
  2. Update to a patched version listed above, then confirm the new version.
  3. Review logs and exposed services for signs of earlier compromise.

Timeline

  • Jul 3, 2026Published
  • Jul 7, 2026Record last modified

Score, severity and exploitation changes are tracked from the day Watchtower started logging them.

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Related Coverage

External References

Data last checked: Nov 15, 2026 03:31 UTC