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OCSP stapling verification bypass in cURL

Published: 2017-02-22
Severity Medium
Patch available YES
Number of vulnerabilities 1
CVE ID CVE-2017-2629
Exploitation vector Network
Public exploit N/A
Vulnerable software
Client/Desktop applications / Other client software


Security Advisory

This security advisory describes one medium risk vulnerability.

1) Security bypass

Severity: Medium

CVSSv3: 7.2 [CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L/E:U/RL:O/RC:C] [PCI]

CVE-ID: CVE-2017-2629

CWE-ID: CWE-295 - Improper Certificate Validation

Exploit availability: No


The vulnerability allows a remote attacker to bypass certain security restrictions.

The vulnerability exists due to an error within TLS Certificate Status Request extension implementation (a.k.a OCSP stapling) in cURL. The problem is caused by coding error, when the affected function returns positive result even when there is none or if the server doesn't support the TLS extension in question. A remote attacker can bypass CURLOPT_SSL_VERIFYSTATUS option and make the affected system treat all requests as valid.

Successful exploitation of the vulnerability may allow an attacker to bypass implemented security controls and perform a MitM or phishing attack.


Update to version 7.53.0

Vulnerable software versions

cURL: 7.52.0, 7.52.1

CPE External links

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.