CVE-2025-40322
Published Dec 8, 2025
Modified Apr 15, 2026
Description
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.
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References
Other References
https://git.kernel.org/stable/c/0998a6cb232674408a03e8561dc15aa266b2f53b
https://git.kernel.org/stable/c/18c4ef4e765a798b47980555ed665d78b71aeadf
https://git.kernel.org/stable/c/901f44227072be60812fe8083e83e1533c04eed1
https://git.kernel.org/stable/c/9ba1a7802ca9a2590cef95b253e6526f4364477f
https://git.kernel.org/stable/c/a10cede006f9614b465cf25609a8753efbfd45cc
https://git.kernel.org/stable/c/c12003bf91fdff381c55ef54fef3e961a5af2545
https://git.kernel.org/stable/c/db5c9a162d2f42bcc842b76b3d935dcc050a0eec
https://git.kernel.org/stable/c/efaf89a75a29b2d179bf4fe63ca62852e93ad620
Frequently Asked Questions
What is CVE-2025-40322? +
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.
How do I check if I'm vulnerable to CVE-2025-40322? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.