GNU Tar through 1.30, when —sparse is used, mishandles file shrinkage during read access, which allows local users to cause
a denial of service (infinite read loop in sparse_dump_region in sparse.c) by modifying a file that is supposed to be archived by
a different user’s process (e.g., a system backup running as root).

References:

https://utcc.utoronto.ca/~cks/space/blog/sysadmin/TarFindingTruncateBug
https://nvd.nist.gov/vuln/detail/CVE-2018-20482

Patch:

http://git.savannah.gnu.org/cgit/tar.git/commit/?id=c15c42c

(from redmine: issue id 9849, created on 2019-01-10, closed on 2019-01-18)

• Relations:
  • parent #9847 (closed)
• Changesets:
  • Revision e37604c4 on 2019-01-17T15:22:38Z:

main/tar: security upgrade to 1.31

fixes #9849