The Linux kernel temperature monitoring subsystem contains a buffer overflow that occurs when the q54sj108a2_debugfs_read function processes a 32-byte block read from an I2C device. Because the bin2hex() helper receives the destination and source pointers swapped, it writes 64 bytes of hex output into a 34-byte buffer, overflowing the stack. The overflow corrupts adjacent kernel memory and can enable a local attacker with access to the /sys/kernel/debug interface to execute arbitrary code or cause a denial of service.

Affected systems are all Linux kernel releases that include the unpatched pmbus/q54sj108a2 driver, which is part of the standard kernel source tree. The vulnerability is present before the fix committed in the linked kernel patches and disappears in the latest kernel versions that incorporate the patch. Anyone running a kernel that still contains this driver is potentially exposed.

Risk and exploitability: The flaw is local and requires access to the /sys/kernel/debug interface for the pmbus device. While no public exploit exists yet, the stack overwrite creates a high-impact scenario for privileged escalation, and the absence of an EPSS score does not diminish the potential damage. The vulnerability is not currently catalogued in the CISA KEV list, but its severity warrants immediate patching once a kernel update is available.