aptitude segfault if permission denied for /etc/apt/preferences

I have a /etc/apt/preferences file with permission 600. When I run aptitude search PATTERN as a non-root user aptitude crashes with a segfault.

[1] 29308 segmentation fault (core dumped) aptitude search linux

When I change the permissions to 644 it works as expected.

I attached a strace log.

Let me know if I should provide more information.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: aptitude 0.8.10-6ubuntu1
ProcVersionSignature: Ubuntu 4.15.0-72.81-generic 4.15.18
Uname: Linux 4.15.0-72-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.9
Architecture: amd64
Date: Fri Dec 27 23:53:57 2019
SourcePackage: aptitude
UpgradeStatus: No upgrade log present (probably fresh install)