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CVE-2026-10536

Haxx Curl use-after-free

9.8 CRITICALPublic exploitEPSS 0.60%
  1. Published3 Jul 2026

Description

A use-after-free vulnerability exists in libcurl when an application configures an HTTP/2 stream-dependency tree via `CURLOPT_STREAM_DEPENDS` or `CURLOPT_STREAM_DEPENDS_E`, subsequently invokes `curl_easy_reset()`, and finally terminates the handle with `curl_easy_cleanup()`. During this final cleanup phase, libcurl attempts to access and modify an internal structure that was already freed during the reset operation.

CVSS 3.1 breakdown

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

Affected products

Haxx Curl≥ 7.88.0 < 8.21.0

Remediation

Fixed in
Haxx Curl≥ 8.21.0

References

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Frequently asked

Is CVE-2026-10536 being actively exploited?

CVE-2026-10536 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.60%.

How severe is CVE-2026-10536?

CVE-2026-10536 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 0.60% probability of exploitation.

Which products are affected by CVE-2026-10536?

Affected products include Haxx Curl.

How do I fix CVE-2026-10536?

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-2026-10536 against the real software inventory on every managed device, every day. 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.