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Fix buffer access in bitreader.c for consumed bits #179

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Fix buffer access in bitreader.c for consumed bits #179

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4bae3c4
Fix buffer access in bitreader.c for consumed bits
Mrcopytuo Dec 13, 2025
7eab214
Fix buffer access in genesis bitreader.c
Mrcopytuo Dec 17, 2025
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2 changes: 1 addition & 1 deletion cores/genesis/core/cd_hw/libchdr/deps/libFLAC/bitreader.c
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Original file line number Diff line number Diff line change
Expand Up @@ -859,7 +859,7 @@ FLAC__bool FLAC__bitreader_read_rice_signed_block(FLAC__BitReader *br, int vals[
cwords = br->consumed_words;
words = br->words;
ucbits = FLAC__BITS_PER_WORD - br->consumed_bits;
b = br->buffer[cwords] << br->consumed_bits;
b = cwords < br->capacity ? br->buffer[cwords] << br->consumed_bits : 0;
} while(cwords >= words && val < end);
}

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2 changes: 1 addition & 1 deletion cores/pce/deps/flac-1.3.2/src/libFLAC/bitreader.c
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Original file line number Diff line number Diff line change
Expand Up @@ -859,7 +859,7 @@ FLAC__bool FLAC__bitreader_read_rice_signed_block(FLAC__BitReader *br, int vals[
cwords = br->consumed_words;
words = br->words;
ucbits = FLAC__BITS_PER_WORD - br->consumed_bits;
b = br->buffer[cwords] << br->consumed_bits;
b = cwords < br->capacity ? br->buffer[cwords] << br->consumed_bits : 0;

Copilot AI Dec 16, 2025

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This security fix appears to only address one instance of the FLAC library in this repository. The Genesis core also has a copy of the FLAC library at cores/genesis/core/cd_hw/libchdr/deps/libFLAC/bitreader.c that contains the same vulnerability at line 862. Consider applying the same fix to that location to ensure comprehensive protection against CVE-2020-0499.

Suggested change
b = cwords < br->capacity ? br->buffer[cwords] << br->consumed_bits : 0;
b = cwords < words ? br->buffer[cwords] << br->consumed_bits : 0;

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} while(cwords >= words && val < end);
}

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