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CVE-2026-12064

Haxx Curl vulnerability

7.5 HIGHPublic exploitEPSS 0.40%
  1. Published3 Jul 2026

Description

When a user invokes curl using a schemeless URL combined with `--proto-default` sftp (or scp), a disconnect occurs between the tool layer and libcurl. The tool layer incorrectly infers the URL scheme, which erroneously bypasses the initialization of critical SSH security options like CURLOPT_SSH_HOST_PUBLIC_KEY_SHA256 and CURLOPT_SSH_KNOWNHOSTS. Conversely, the libcurl runtime successfully honors CURLOPT_DEFAULT_PROTOCOL and establishes the connection via SFTP/SCP as specified. Because the tool layer skipped the security configuration, these SSH host verification options are silently omitted, causing curl to connect to an unverified SSH remote host without throwing an error.

CVSS 3.1 breakdown

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

Affected products

Haxx Curl≥ 7.81.0 < 8.21.0

Remediation

Fixed in
Haxx Curl≥ 8.21.0

References

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Frequently asked

Is CVE-2026-12064 being actively exploited?

CVE-2026-12064 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.40%.

How severe is CVE-2026-12064?

CVE-2026-12064 has a CVSS 3.1 base score of 7.5, rated high. EPSS estimates a 0.40% probability of exploitation.

Which products are affected by CVE-2026-12064?

Affected products include Haxx Curl.

How do I fix CVE-2026-12064?

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-2026-12064 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.