GHSA-gm37-qx7w-p258

A memory leak in the ASHLAR image writer allows an attacker to exhaust process memory by providing a crafted image that results in small objects that are allocated but never freed.

``` ==880062== Memcheck, a memory error detector ==880062== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al. ==880062== Using Valgrind-3.18.1 and LibVEX; rerun with -h for copyright info ==880062== ==880062== ==880062== HEAP SUMMARY: ==880062== in use at exit: 386,826 bytes in 696 blocks ==880062== total heap usage: 30,523 allocs, 29,827 frees, 21,803,756 bytes allocated ==880062== ==880062== LEAK SUMMARY: ==880062== definitely lost: 3,408 bytes in 3 blocks ==880062== indirectly lost: 88,885 bytes in 30 blocks ==880062== possibly lost: 140,944 bytes in 383 blocks ==880062== still reachable: 151,573 bytes in 259 blocks ==880062== suppressed: 0 bytes in 0 blocks ==880062== Reachable blocks (those to which a pointer was found) are not shown. ==880062== To see them, rerun with: --leak-check=full --show-leak-kinds=all ==880062== ==880062== For lists of detected and suppressed errors, rerun with: -s ==880062== ERROR SUMMARY: 2 errors from 2 contexts (suppressed: 0 from 0) ```