HFS+: Validate compressed attribute record bounds#1708
Merged
val-ms merged 1 commit intoCisco-Talos:mainfrom Apr 27, 2026
Merged
HFS+: Validate compressed attribute record bounds#1708val-ms merged 1 commit intoCisco-Talos:mainfrom
val-ms merged 1 commit intoCisco-Talos:mainfrom
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The HFS+ compressed-file attribute parser validated the attribute name length as a UTF-16 character count, but later used that same field as a byte offset by multiplying it by two. A crafted attribute record could therefore place the inline attribute record header near the end of the node and trigger an out-of-bounds read when ClamAV copied the record header or payload. Fix this by converting the attribute name length to a checked byte count before using it in offset calculations. Validate that the inline attribute record header fits in the node before reading it, and verify that the claimed attribute payload also fits before copying it. Credit: Sebastián Alba Vives CLAM-2969
jhumlick
approved these changes
Apr 9, 2026
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The HFS+ compressed-file attribute parser validated the attribute name length as a UTF-16 character count, but later used that same field as a byte offset by multiplying it by two. A crafted attribute record could therefore place the inline attribute record header near the end of the node and trigger an out-of-bounds read when ClamAV copied the record header or payload.
This read does not cause a crash on any systems we tested and we do not consider this issue to be a security issue.
Fix this by converting the attribute name length to a checked byte count before using it in offset calculations. Validate that the inline attribute record header fits in the node before reading it, and verify that the claimed attribute payload also fits before copying it.
Credit: Sebastián Alba Vives
CLAM-2969