DB_LOOKUP in nss_files/files-XXX.c in the Name Service Switch (NSS) in GNU C Library (aka glibc or libc6) 2.21 and earlier does not properly check if a file is open, which allows remote attackers to cause a denial of service (infinite loop) by performing a look-up while the database is iterated over the database, which triggers the file pointer to be reset. http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2014-8121
