Bug 2429078 (CVE-2025-68816)

Summary: CVE-2025-68816 kernel: Linux kernel: mlx5 firmware tracer vulnerable to arbitrary memory access or denial of service via malformed format strings
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: medium    
Version: unspecifiedKeywords: Security
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OS: Linux   
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A flaw was found in the Linux kernel's mlx5 firmware tracer. A malicious or compromised firmware can provide specially crafted format strings to the tracer. Due to insufficient validation of these parameters, this can lead to system crashes, resulting in a Denial of Service (DoS), or potentially allow access to arbitrary memory locations.
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Description OSIDB Bzimport 2026-01-13 16:05:09 UTC 
In the Linux kernel, the following vulnerability has been resolved:

net/mlx5: fw_tracer, Validate format string parameters

Add validation for format string parameters in the firmware tracer to
prevent potential security vulnerabilities and crashes from malformed
format strings received from firmware.

The firmware tracer receives format strings from the device firmware and
uses them to format trace messages. Without proper validation, bad
firmware could provide format strings with invalid format specifiers
(e.g., %s, %p, %n) that could lead to crashes, or other undefined
behavior.

Add mlx5_tracer_validate_params() to validate that all format specifiers
in trace strings are limited to safe integer/hex formats (%x, %d, %i,
%u, %llx, %lx, etc.). Reject strings containing other format types that
could be used to access arbitrary memory or cause crashes.
Invalid format strings are added to the trace output for visibility with
"BAD_FORMAT: " prefix.
Comment 1 Jon Moroney 2026-01-15 00:56:07 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026011313-CVE-2025-68816-e773@gregkh/T