CVE-2015-1472

Vulnerability

The vulnerability resides in the ADDW macro within stdio-common/vfscanf.c of the GNU C Library (glibc) before version 2.21. The macro does not properly account for the size of the wide-character data type during memory allocation, leading to a potential buffer overflow when processing a long line containing wide characters. This flaw is triggered through a wscanf call [2] [3] [4].

Exploitation

An attacker needs only the ability to supply a specially crafted input string containing a long sequence of wide characters to a program using wscanf. No special authentication or network position is required beyond the ability to deliver the input to the vulnerable function. The exploitation occurs through the misuse of the ADDW macro, which fails to allocate sufficient buffer space [2] [3] [4].

Impact

Successful exploitation results in a buffer overflow, leading to a denial of service (DoS) due to memory corruption. The official description also notes the possibility of "unspecified other impact," which could include arbitrary code execution depending on the context [2] [3] [4].

Mitigation

The vulnerability is fixed in glibc version 2.21, released on 2015-02-06. Systems running glibc earlier than 2.21 should upgrade immediately. No workarounds are documented; the only mitigation is to apply the updated library [2] [3] [4].