From 5f91c6b38e7d9ac69a80de65b4b7630f3607538c Mon Sep 17 00:00:00 2001 From: Andrew Murray Date: Wed, 18 Feb 2026 23:28:51 +1100 Subject: [PATCH] Only read as much data from gzip-decompressed data as necessary --- src/PIL/FitsImagePlugin.py | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-) diff --git a/src/PIL/FitsImagePlugin.py b/src/PIL/FitsImagePlugin.py index a3fdc0efeec..e918407784d 100644 --- a/src/PIL/FitsImagePlugin.py +++ b/src/PIL/FitsImagePlugin.py @@ -128,17 +128,18 @@ class FitsGzipDecoder(ImageFile.PyDecoder): def decode(self, buffer: bytes | Image.SupportsArrayInterface) -> tuple[int, int]: assert self.fd is not None - value = gzip.decompress(self.fd.read()) - - rows = [] - offset = 0 - number_of_bits = min(self.args[0] // 8, 4) - for y in range(self.state.ysize): - row = bytearray() - for x in range(self.state.xsize): - row += value[offset + (4 - number_of_bits) : offset + 4] - offset += 4 - rows.append(row) + with gzip.open(self.fd) as fp: + value = fp.read(self.state.xsize * self.state.ysize * 4) + + rows = [] + offset = 0 + number_of_bits = min(self.args[0] // 8, 4) + for y in range(self.state.ysize): + row = bytearray() + for x in range(self.state.xsize): + row += value[offset + (4 - number_of_bits) : offset + 4] + offset += 4 + rows.append(row) self.set_as_raw(bytes([pixel for row in rows[::-1] for pixel in row])) return -1, 0