Recently there was a new vulnerability introduced in glibc library: http://www.openwall.com/lists/oss-security/2015/01/27/9
Oracle is using the gethostbyname function in "*skgxp*" libraries:
oracle@kokos:~$ find /u01/ -name "*skgxp*" -type f | awk '{system("nm " $0 " | grep gethostbyname && echo "$0)}' 2>/dev/null U gethostbyname /u01/app/oracle/product/12.1.0.1/rdbms/lib/libskgxpr.a U gethostbyname /u01/app/oracle/product/12.1.0.1/rdbms/lib/libskgxpg.a U gethostbyname@@GLIBC_2.2.5 /u01/app/oracle/product/12.1.0.1/lib/libskgxpg.so U gethostbyname@@GLIBC_2.2.5 /u01/app/oracle/product/12.1.0.1/lib/libskgxpr.so U gethostbyname@@GLIBC_2.2.5 /u01/app/oracle/product/12.1.0.1/lib/libskgxp12.so U gethostbyname@@GLIBC_2.2.5 /u01/app/oracle/product/12.1.0.1/inventory/backup/2014-07-21_08-23-18PM/Scripts/ext/lib/libskgxp12.so U gethostbyname@@GLIBC_2.2.5 /u01/app/oracle/product/12.1.0.1/inventory/Scripts/ext/lib/libskgxp12.so U gethostbyname /u01/app/oracle/product/12.1.0.2/rdbms/lib/libskgxpr.a U gethostbyname /u01/app/oracle/product/12.1.0.2/rdbms/lib/libskgxpg.a U gethostbyname@@GLIBC_2.2.5 /u01/app/oracle/product/12.1.0.2/lib/libskgxpg.so U gethostbyname@@GLIBC_2.2.5 /u01/app/oracle/product/12.1.0.2/lib/libskgxpr.so U gethostbyname@@GLIBC_2.2.5 /u01/app/oracle/product/12.1.0.2/lib/libskgxp12.so U gethostbyname@@GLIBC_2.2.5 /u01/app/oracle/product/12.1.0.2/inventory/backup/2014-07-21_08-40-47PM/Scripts/ext/lib/libskgxp12.so U gethostbyname@@GLIBC_2.2.5 /u01/app/oracle/product/12.1.0.2/inventory/Scripts/ext/lib/libskgxp12.so U gethostbyname /u01/app/oracle/product/11.2.0/rdbms/lib/libskgxpr.a U gethostbyname /u01/app/oracle/product/11.2.0/rdbms/lib/libskgxpg.a U gethostbyname@@GLIBC_2.2.5 /u01/app/oracle/product/11.2.0/lib/libskgxpg.so U gethostbyname@@GLIBC_2.2.5 /u01/app/oracle/product/11.2.0/lib/libskgxpr.so U gethostbyname@@GLIBC_2.2.5 /u01/app/oracle/product/11.2.0/lib/libskgxp11.so U gethostbyname@@GLIBC_2.2.5 /u01/app/oracle/product/11.2.0/inventory/backup/2013-10-14_03-30-09PM/Scripts/ext/lib/libskgxp11.so U gethostbyname@@GLIBC_2.2.5 /u01/app/oracle/product/11.2.0/inventory/Scripts/ext/lib/libskgxp11.so
So this can be an issue – a specially in RAC environments.
RedHat recommends to upgrade the glibc libraries:
https://access.redhat.com/articles/1332213
And I do agree 😉