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CVE Radar
HighcURL

CVE-2021-22946

A user can tell curl >= 7.20.0 and <= 7.78.0 to require a successful upgrade to TLS when speaking to an IMAP, POP3 or FTP server (`--ssl-reqd` on the command line or`CURLOPT_USE_SSL` set to `CURLUSESSL_CONTROL` or `CURLUSESSL_ALL` withlibcurl). This requirement could be bypassed if the server would return a properly crafted but perfectly legitimate response.This flaw would then make curl silently continue its operations **withoutTLS** contrary to the instructions and expectations, exposing possibly sensitive data in clear text over the network.

CVSS Base Score
7.5

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Exploit Probability
91%EPSS PERCENTILE0100

More exploitable than 91% of all CVEs · Top 9%

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Details
Published
2021-09-29
Last modified
2026-10-14
Affected
cURL

Data from the National Vulnerability Database (NVD), CISA KEV, and FIRST.org EPSS. This product uses the NVD API but is not endorsed or certified by the NVD. EPSS is a probability estimate, not a guarantee of exploitation.