Bug 2464399 (CVE-2026-31747)

Summary: CVE-2026-31747 kernel: comedi: me4000: Fix potential overrun of firmware buffer
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
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Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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Doc Text:
A flaw was found in the Linux kernel's `comedi: me4000` driver. The `me4000_xilinx_download()` function fails to validate the length of the firmware data stream, trusting the value provided in the firmware header. A local attacker could exploit this by providing a specially crafted firmware image, leading to a buffer overrun. This could result in a denial of service (DoS) or potentially other system instabilities.
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Description OSIDB Bzimport 2026-05-01 15:04:36 UTC
In the Linux kernel, the following vulnerability has been resolved:

comedi: me4000: Fix potential overrun of firmware buffer

`me4000_xilinx_download()` loads the firmware that was requested by
`request_firmware()`.  It is possible for it to overrun the source
buffer because it blindly trusts the file format.  It reads a data
stream length from the first 4 bytes into variable `file_length` and
reads the data stream contents of length `file_length` from offset 16
onwards.

Add a test to ensure that the supplied firmware is long enough to
contain the header and the data stream.  On failure, log an error and
return `-EINVAL`.

Note: The firmware loading was totally broken before commit ac584af59945
("staging: comedi: me4000: fix firmware downloading"), but that is the
most sensible target for this fix.