Flawfinder version 2.0.10, (C) 2001-2019 David A. Wheeler.
Number of rules (primarily dangerous function names) in C/C++ ruleset: 223
Examining data/ipv6pref-1.0.3/ipv6pref.c

FINAL RESULTS:

data/ipv6pref-1.0.3/ipv6pref.c:36:15:  [3] (buffer) getenv:
  Environment variables are untrustable input if they can be set by an
  attacker. They can have any content and length, and the same variable can
  be set more than once (CWE-807, CWE-20). Check environment variables
  carefully before using them.
	char *pref = getenv("IPV6PREF_ADDR");

ANALYSIS SUMMARY:

Hits = 1
Lines analyzed = 86 in approximately 0.02 seconds (4429 lines/second)
Physical Source Lines of Code (SLOC) = 58
Hits@level = [0]   0 [1]   0 [2]   0 [3]   1 [4]   0 [5]   0
Hits@level+ = [0+]   1 [1+]   1 [2+]   1 [3+]   1 [4+]   0 [5+]   0
Hits/KSLOC@level+ = [0+] 17.2414 [1+] 17.2414 [2+] 17.2414 [3+] 17.2414 [4+]   0 [5+]   0
Dot directories skipped = 1 (--followdotdir overrides)
Minimum risk level = 1
Not every hit is necessarily a security vulnerability.
There may be other security vulnerabilities; review your code!
See 'Secure Programming HOWTO'
(https://dwheeler.com/secure-programs) for more information.