cURL up to 8.20.0 Configuration certificate host validation

Summaryinfo

A vulnerability was found in cURL. It has been rated as problematic. This issue affects some unknown processing of the component Configuration Handler. The manipulation leads to certificate host validation. This vulnerability is documented as CVE-2026-12064. The attack can be initiated remotely. There is not any exploit available.

Detailsinfo

A vulnerability was found in cURL and classified as problematic. This issue affects an unknown function of the component Configuration Handler. The manipulation with an unknown input leads to a certificate host validation vulnerability. Using CWE to declare the problem leads to CWE-297. The product communicates with a host that provides a certificate, but the product does not properly ensure that the certificate is actually associated with that host. Impacted is integrity. The summary by CVE is:

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.

The weakness was released by Alienowo. The advisory is shared at curl.se. The identification of this vulnerability is CVE-2026-12064 since 06/12/2026. The exploitation is known to be difficult. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 07/03/2026). MITRE ATT&CK project uses the attack technique T1587.003 for this issue.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Type

• Network Utility Software

Name

• cURL

Version

• 7.0
• 7.1
• 7.2
• 7.3
• 7.4
• 7.5
• 7.6
• 7.7
• 7.8
• 7.9
• 7.10
• 7.11
• 7.12
• 7.13
• 7.14
• 7.15
• 7.16
• 7.17
• 7.18
• 7.19
• 7.20
• 7.21
• 7.22
• 7.23
• 7.24
• 7.25
• 7.26
• 7.27
• 7.28
• 7.29
• 7.30
• 7.31
• 7.32
• 7.33
• 7.34
• 7.35
• 7.36
• 7.37
• 7.38
• 7.39
• 7.40
• 7.41
• 7.42
• 7.43
• 7.44
• 7.45
• 7.46
• 7.47
• 7.48
• 7.49
• 7.50
• 7.51
• 7.52
• 7.53
• 7.54
• 7.55
• 7.56
• 7.57
• 7.58
• 7.59
• 7.60
• 7.61
• 7.62
• 7.63
• 7.64
• 7.65
• 7.66
• 7.67
• 7.68
• 7.69
• 7.70
• 7.71
• 7.72
• 7.73
• 7.74
• 7.75
• 7.76
• 7.77
• 7.78
• 7.79
• 7.80
• 7.81
• 7.81.0
• 7.82
• 7.82.0
• 7.83
• 7.83.0
• 7.83.1
• 7.84
• 7.84.0
• 7.85
• 7.85.0
• 7.86
• 7.86.0
• 7.87
• 7.87.0
• 7.88.0
• 7.88.1
• 8.0
• 8.0.0
• 8.0.1
• 8.1
• 8.1.0
• 8.1.1
• 8.1.2
• 8.2
• 8.2.0
• 8.2.1
• 8.3
• 8.3.0
• 8.4
• 8.4.0
• 8.5
• 8.5.0
• 8.6
• 8.6.0
• 8.7
• 8.7.0
• 8.7.1
• 8.8
• 8.8.0
• 8.9
• 8.9.0
• 8.9.1
• 8.10
• 8.10.0
• 8.10.1
• 8.11
• 8.11.0
• 8.11.1
• 8.12
• 8.12.0
• 8.12.1
• 8.13
• 8.13.0
• 8.14
• 8.14.0
• 8.14.1
• 8.15
• 8.15.0
• 8.16
• 8.16.0
• 8.17
• 8.17.0
• 8.18
• 8.18.0
• 8.19
• 8.19.0
• 8.20.0

License

• open-source

CPE 2.3info

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CPE 2.2info

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Entryinfo

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