Summary:

    Potential code execution with tar.vim and special crafted tar
    files.

Description:

    Vim is distributed with the tar.vim plugin, that allows easy
    editing and viewing of (compressed or uncompressed) tar files.

    Since commit 129a844 (Nov 11, 2024 runtime(tar): Update tar.vim to
    support permissions), the tar.vim plugin uses the ":read " ex
    command line to append below the cursor position, however the is
    not sanitized and is taken literaly from the tar archive. This
    allows to execute shell commands via special crafted tar archives.
    Whether this really happens, depends on the shell being used
    ('shell' option, which is set using $SHELL).

Impact:

    Impact is high but a user must be convinced to edit such a file
    using Vim which will reveal the filename, so a careful user may
    suspect some strange things going on.

The Vim project would like to thank RyotaK (GMO Flatt Security Inc)
for reporting this issue.

The issue has been fixed as of Vim patch v9.1.1164.