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CVE-2025-38004: can: bcm: add locking for bcm_op runtime updates

Description

In the Linux kernel, the following vulnerability has been resolved:

can: bcm: add locking for bcm_op runtime updates

The CAN broadcast manager (CAN BCM) can send a sequence of CAN frames via
hrtimer. The content and also the length of the sequence can be changed
resp reduced at runtime where the 'currframe' counter is then set to zero.

Although this appeared to be a safe operation the updates of 'currframe'
can be triggered from user space and hrtimer context in bcm_can_tx().
Anderson Nascimento created a proof of concept that triggered a KASAN
slab-out-of-bounds read access which can be prevented with a spin_lock_bh.

At the rework of bcm_can_tx() the 'count' variable has been moved into
the protected section as this variable can be modified from both contexts
too.

Classification

CVE ID: CVE-2025-38004

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.03% (probability of being exploited)

EPSS Percentile: 7.51% (scored less or equal to compared to others)

EPSS Date: 2025-06-27 (when was this score calculated)

References

Timeline

2025-06-08 11:40:10 UTC
CVE

can: bcm: add locking for bcm_op runtime updates