curl segfaults during network access with invalid -F argument

[Matthew Toseland]

mjt@i4-desktop:~/tmp$ vi 1.html
mjt@i4-desktop:~/tmp$ curl -F'file=1.html' http://0x0.st
Segmentation fault
mjt@i4-desktop:~/tmp$ curl -v -F'file=1.html' http://0x0.st
* Rebuilt URL to: http://0x0.st/
* Trying 136.243.89.164...
* TCP_NODELAY set
* Connected to 0x0.st (136.243.89.164) port 80 (#0)
> POST / HTTP/1.1
> Host: 0x0.st
> User-Agent: curl/7.58.0
> Accept: */*
> Content-Length: 145
> Content-Type: multipart/form-data; boundary=------------------------ee207a15c83a6272
>
< HTTP/1.1 400 BAD REQUEST
< Server: nginx
< Date: Thu, 23 Jan 2020 16:36:43 GMT
< Content-Type: text/html; charset=utf-8
< Content-Length: 19
< Connection: keep-alive
* HTTP error before end of send, stop sending
<
Segmentation fault
* Closing connection 0

mjt@i4-desktop:~/tmp$ curl --version
curl 7.58.0 (x86_64-pc-linux-gnu) libcurl/7.58.0 OpenSSL/1.1.1 zlib/1.2.11 libidn2/2.0.4 libpsl/0.19.1 (+libidn2/2.0.4) nghttp2/1.30.0 librtmp/2.3
Release-Date: 2018-01-24
Protocols: dict file ftp ftps gopher http https imap imaps ldap ldaps pop3 pop3s rtmp rtsp smb smbs smtp smtps telnet tftp
Features: AsynchDNS IDN IPv6 Largefile GSS-API Kerberos SPNEGO NTLM NTLM_WB SSL libz TLS-SRP HTTP2 UnixSockets HTTPS-proxy PSL

mjt@i4-desktop:~/tmp$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 18.04.3 LTS
Release: 18.04
Codename: bionic