[File] [SECURITY] Heap Buffer Over-read in softmagic.c FILE_OPINDIRECT Handling (file-5.17)

[Christos Zoulas]

There are checks already, but I added an extra one.

Best,

christos

> On Apr 1, 2026, at 10:58 AM, Kerwin <kerwinxia66001 at gmail.com> wrote:
> 
> Hi maintainers,
> 
> I am reporting a heap buffer over-read vulnerability in libmagic (file-5.17) where the FILE_OPINDIRECT code path in `mget()` (softmagic.c:1189-1222) dereferences a computed pointer before any bounds check against `nbytes`, allowing an out-of-bounds heap read when a crafted magic database is loaded.
> 
> Please find the detailed vulnerability report and proof-of-concept files attached.
> 
> Best regards
> 
> <POC.tar>-- 
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