CVE-2025-40304
In the Linux kernel, the following vulnerability has been resolved: fbdev: Add bounds checking in bit_putcs to fix vmalloc-out-of-bounds Add bounds checking to prevent writes past framebuffer boundaries when rendering text near screen edges. Return early if the Y position is off-screen and clip image height to screen boundary. Break from the rendering loop if the X position is off-screen. When clipping image width to fit the screen, update the character count to match the clipped width to prevent buffer size mismatches. Without the character count update, bit_putcs_aligned and bit_putcs_unaligned receive mismatched parameters where the buffer is allocated for the clipped width but cnt reflects the original larger count, causing out-of-bounds writes.
Affected versions
Linux kernel versions
2.6.12
and later are affected. Fixed in
5.4.302,
5.10.247,
5.15.197,
6.1.159,
6.6.117,
6.12.58,
6.17.8,
6.18
and their respective stable series.
References
The following references provide additional information about CVE-2025-40304 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.
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PatchKernel patch commithttps://git.kernel.org/stable/c/15ba9acafb0517f8359ca30002c189a68ddbb939
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PatchKernel patch commithttps://git.kernel.org/stable/c/1943b69e87b0ab35032d47de0a7fca9a3d1d6fc1
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PatchKernel patch commithttps://git.kernel.org/stable/c/2d1359e11674ed4274934eac8a71877ae5ae7bbb
Frequently asked questions
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What is CVE-2025-40304?
CVE-2025-40304 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 2.6.12 onward and has been patched in 5.4.302, 5.10.247, 5.15.197 and others. CVE-2025-40304 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2025-40304?
Yes — CVE-2025-40304 has been patched. Fixed versions include 5.4.302, 5.10.247, 5.15.197 and others. If you are running Linux kernel 2.6.12 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2025-40304 actively exploited?
No — CVE-2025-40304 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.