Bug 2419902 (CVE-2025-40322)

Summary: CVE-2025-40322 kernel: fbdev: bitblit: bound-check glyph index in bit_putcs*
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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OS: Linux   
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Description OSIDB Bzimport 2025-12-08 07:07:25 UTC 
In the Linux kernel, the following vulnerability has been resolved:

fbdev: bitblit: bound-check glyph index in bit_putcs*

bit_putcs_aligned()/unaligned() derived the glyph pointer from the
character value masked by 0xff/0x1ff, which may exceed the actual font's
glyph count and read past the end of the built-in font array.
Clamp the index to the actual glyph count before computing the address.

This fixes a global out-of-bounds read reported by syzbot.
Comment 1 Jon Moroney 2025-12-08 21:09:56 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025120823-CVE-2025-40322-6355@gregkh/T