CVE-2021-22947

When curl >= 7.20.0 and <= 7.78.0 connects to an IMAP or POP3 server to retrieve data using STARTTLS to upgrade to TLS security, the server can respond and send back multiple responses at once that curl caches. curl would then upgrade to TLS but not flush the in-queue of cached responses but instead continue using and trustingthe responses it got before the TLS handshake as if they were authenticated.Using this flaw, it allows a Man-In-The-Middle attacker to first inject the fake responses, then pass-through the TLS traffic from the legitimate server and trick curl into sending data back to the user thinking the attackers injected data comes from the TLS-protected server.

Affected Software

Name	Vendor	Start Version	End Version
Curl	Haxx	7.20.0 (including)	7.79.0 (excluding)
.NET Core on Red Hat Enterprise Linux	RedHat	rh-dotnet31-curl-0:7.61.1-22.el7_9	*
Red Hat Enterprise Linux 8	RedHat	curl-0:7.61.1-18.el8_4.2	*
Red Hat Enterprise Linux 8.2 Extended Update Support	RedHat	curl-0:7.61.1-12.el8_2.4	*
Curl	Ubuntu	bionic	*
Curl	Ubuntu	devel	*
Curl	Ubuntu	esm-infra-legacy/trusty	*
Curl	Ubuntu	esm-infra/bionic	*
Curl	Ubuntu	esm-infra/focal	*
Curl	Ubuntu	esm-infra/xenial	*
Curl	Ubuntu	focal	*
Curl	Ubuntu	hirsute	*
Curl	Ubuntu	impish	*
Curl	Ubuntu	jammy	*
Curl	Ubuntu	trusty	*
Curl	Ubuntu	trusty/esm	*
Curl	Ubuntu	xenial	*

NVD	https://nvd.nist.gov/vuln/detail/CVE-2021-22947
CWE	https://cwe.mitre.org/data/definitions/310.html

Affected Software

References