Hi!

I've received some concerned questions about curl and the glibc issue CVE-2015-7547 that Google among others has blogged about [1].

The issue they discovered is really within glibc's getaddrinfo() function and makes it vulnerable to crafted DNS server responses. Like if there's a malicious DNS server or another process snooping the network and sending spoofed DNS server responses very well timed.

curl uses getaddrinfo() on most platforms so in that sense it is vulnerable,
but it also can't protect itself against this vulnerability since curl is not
doing anything wrong here. The best fix is to patch glibc.

A work-around can be to build against c-ares instead or switch off IPv6 abilities with configure, which would make curl use the older gethostbyname API in glibc that isn't vulnerable.

[1] = https://googleonlinesecurity.blogspot.com/2016/02/cve-2015-7547-glibc-getaddrin
fo-stack.html

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