|Description||In curl before 7.86.0, the HSTS check could be bypassed to trick it into staying with HTTP. Using its HSTS support, curl can be instructed to use HTTPS directly (instead of using an insecure cleartext HTTP step) even when HTTP is provided in the URL. This mechanism could be bypassed if the host name in the given URL uses IDN characters that get replaced with ASCII counterparts as part of the IDN conversion, e.g., using the character UTF-8 U+3002 (IDEOGRAPHIC FULL STOP) instead of the common ASCII full stop of U+002E (.). The earliest affected version is 7.77.0 2021-05-26.|
|Source||CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)|
Vulnerable and fixed packages
The table below lists information on source packages.
|bullseye (security), bullseye||7.74.0-1.3+deb11u7||vulnerable|
The information below is based on the following data on fixed versions.
|Package||Type||Release||Fixed Version||Urgency||Origin||Debian Bugs|
[bullseye] - curl <ignored> (curl is not built with HSTS support)
[buster] - curl <not-affected> (Vulnerable code not present)
Introduced with: https://github.com/curl/curl/commit/7385610d0c74c6a254fea5e4cd6e1d559d848c8c (curl-7_74_0)
Enabled by default since: https://github.com/curl/curl/commit/d71ff2b9db566b3f4b2eb29441c2df86715d4339 (curl-7_77_0)
Fixed by: https://github.com/curl/curl/commit/53bcf55b4538067e6dc36242168866becb987bb7 (curl-7_86_0)