CVE-2020-16593: 
NixOS vulnerability analysis and mitigation

A Null Pointer Dereference vulnerability (CVE-2020-16593) was identified in the Binary File Descriptor (BFD) library (aka libbfd) as distributed in GNU Binutils 2.35. The vulnerability specifically exists in the scan_unit_for_symbols function, which can be demonstrated through the addr2line utility. This security flaw was discovered on April 15, 2020, and affects various systems and software that incorporate GNU Binutils (NVD, Bugzilla).

The vulnerability is characterized by a null pointer dereference in the scan_unit_for_symbols function within the BFD library. The issue occurs when processing certain crafted files using the addr2line utility. The vulnerability has been assigned a CVSS v3.1 base score of 5.5 (Medium) with the vector string CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H, indicating local attack vector, low attack complexity, no privileges required, and user interaction required (NVD).

When successfully exploited, this vulnerability can lead to a denial of service (DoS) condition through the processing of specially crafted files. The impact primarily affects the availability of the system, with no direct impact on confidentiality or integrity (NetApp Advisory).

The vulnerability requires local access and user interaction to be exploited. A proof of concept (PoC) was developed and reported to demonstrate the null pointer dereference issue in addr2line. The exploit triggers a segmentation fault when processing specially crafted input files (Bugzilla).

The vulnerability was fixed in GNU Binutils through a patch that prevents strdup(0) calls in the scan_unit_for_symbols function. The fix was committed by Alan Modra on April 16, 2020. Various vendors have released patches for their affected products, including NetApp which has provided specific updates for their SolidFire & HCI Management Node and ONTAP Select Deploy administration utility (Bugzilla, NetApp Advisory).