The ADDW macro in stdio-common/vfscanf.c in the GNU C Library (aka glibc or libc6) before 2.21 does not properly consider data-type size during memory allocation, which allows context-dependent attackers to cause a denial of service (buffer overflow) or possibly have unspecified other impact via a long line containing wide characters that are improperly handled in a wscanf call.

Affected: Ubuntu:14.04:LTS: eglibc

Arnaud Le Blanc discovered that the GNU C Library incorrectly handled file descriptors when resolving DNS queries under high load. This may cause a denial of service in other applications, or an information leak. This issue only affected Ubuntu 10.04 LTS, Ubuntu 12.04 LTS and Ubuntu 14.04 LTS. (CVE-2013-7423)

It was discovered that the GNU C Library incorrectly handled receiving a positive answer while processing the network name when performing DNS resolution. A remote attacker could use this issue to cause the GNU C Library to hang, resulting in a denial of service. (CVE-2014-9402)

Joseph Myers discovered that the GNU C Library wscanf function incorrectly handled memory. A remote attacker could possibly use this issue to cause the GNU C Library to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only affected Ubuntu 12.04 LTS, Ubuntu 14.04 LTS and Ubuntu 14.10. (CVE-2015-1472, CVE-2015-1473)