How severe is CVE-2026-12064?

CVE-2026-12064 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2026-12064 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (38th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-12064?

CVE-2026-12064 affects Haxx Curl. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-12064?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2026-12064 published?

CVE-2026-12064 was published on 2026-07-03 and last updated on 2026-07-07.

CVE-2026-12064

CVE-2026-12064 is a high-severity vulnerability in Haxx Curl with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-295.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 0% (38th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-295
Affected product: Haxx Curl
Published: 2026-07-03
Last modified: 2026-07-07

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.

Frequently asked questions

What is CVE-2026-12064?: 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.
How severe is CVE-2026-12064?: CVE-2026-12064 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2026-12064 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (38th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-12064?: CVE-2026-12064 affects Haxx Curl. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-12064?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2026-12064 published?: CVE-2026-12064 was published on 2026-07-03 and last updated on 2026-07-07.

References

Affected products (1)

cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:*

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