CVE-2021-25289: Correct the fix for CVE-2020-35654#

The previous fix for CVE-2020-35654 was insufficient due to incorrect error checking in TiffDecode.c.

CVE-2021-25290: Fix buffer overflow in TiffDecode.c#

In TiffDecode.c, there is a negative-offset memcpy with an invalid size.

CVE-2021-25291: Fix buffer overflow in TIFFReadRGBATile#

In TiffDecode.c, invalid tile boundaries could lead to an out-of-bounds read in TIFFReadRGBATile.

CVE-2021-25292: Fix DOS attack#

The PDF parser has a catastrophic backtracking regex that could be used as a DOS attack.

CVE-2021-25293: Fix buffer overflow in SgiRleDecode.c#

There is an out-of-bounds read in SgiRleDecode.c since Pillow 4.3.0.

Other Changes#

A crash with the feature flags for libimagequant, libjpeg-turbo, WebP and XCB on unreleased Python 3.10 has been fixed (#5193).