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Review reviewHigh

CVE-2025-40322

Linux

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.

CVSS
7.1
EPSS
0.14%
3.81% percentile
CISA KEV
Not listed
Published
2025.12.08
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability0.14%
Technical severityCVSS 7.1

Vulnerability overview

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.

Affected product and versions

Product
Linux
Affected versions
>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < a10cede006f9614b465cf25609a8753efbfd45cc, >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 0998a6cb232674408a03e8561dc15aa266b2f53b, >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < db5c9a162d2f42bcc842b76b3d935dcc050a0eec, >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < c12003bf91fdff381c55ef54fef3e961a5af2545, >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 9ba1a7802ca9a2590cef95b253e6526f4364477f, >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 901f44227072be60812fe8083e83e1533c04eed1, >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < efaf89a75a29b2d179bf4fe63ca62852e93ad620, >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 18c4ef4e765a798b47980555ed665d78b71aeadf, >= 2.6.12
Fixed versions
No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Linux and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
CWE
Not available