There are 2 open security issues in buster.
2 issues left for the package maintainer to handle:
** DISPUTED ** In the GD Graphics Library (aka LibGD) through 2.2.5, there is a heap-based buffer over-read in tiffWriter in gd_tiff.c. NOTE: the vendor says "In my opinion this issue should not have a CVE, since the GD and GD2 formats are documented to be 'obsolete, and should only be used for development and testing purposes.'"
gdImageClone in gd.c in libgd 2.1.0-rc2 through 2.2.5 has a NULL pointer dereference allowing attackers to crash an application via a specific function call sequence. Only affects PHP when linked with an external libgd (not bundled).
You can find information about how to handle these issues in the security team's documentation.