#VU56613 Cleartext transmission of sensitive information in cURL

Published: 2021-09-15

Vulnerability identifier: #VU56613

Vulnerability risk: Medium

CVSSv3.1: 6.2 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-22946


Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Client/Desktop applications / Other client software

Vendor: curl.haxx.se


The vulnerability allows a remote attacker to gain access to sensitive information.

The vulnerability exists due to an error, related to incorrect enforcement of the --ssl-reqd option on the command line or CURLOPT_USE_SSL setting set to CURLUSESSL_CONTROL or CURLUSESSL_ALL with libcurl. A remote attacker with control over the IMAP, POP3 or FTP server can send a specially crafted but perfectly legitimate response to the libcurl client and force it silently to continue its operations without TLS encryption and transmit data in clear text over the network.

Install updates from vendor's website.

Vulnerable software versions

cURL: 7.20.0 - 7.78.0

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.

Latest bulletins with this vulnerability