CVE-2025-68208

Technical Description

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

bpf: account for current allocated stack depth in widen_imprecise_scalars()

The usage pattern for widen_imprecise_scalars() looks as follows:

prev_st = find_prev_entry(env, ...);

queued_st = push_stack(...);

widen_imprecise_scalars(env, prev_st, queued_st);

Where prev_st is an ancestor of the queued_st in the explored states

tree. This ancestor is not guaranteed to have same allocated stack

depth as queued_st. E.g. in the following case:

def main():

for i in 1..2:

foo(i) // same callsite, differnt param

def foo(i):

if i == 1:

use 128 bytes of stack

iterator based loop

Here, for a second 'foo' call prev_st->allocated_stack is 128,

while queued_st->allocated_stack is much smaller.

widen_imprecise_scalars() needs to take this into account and avoid

accessing bpf_verifier_state->frame[*]->stack out of bounds.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References