CVE-2025-37787: net: dsa: mv88e6xxx: avoid unregistering devlink regions which were never registered

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-05-01 · updated 2026-06-17
Weakness: CWE-476

Description

In the Linux kernel, the following vulnerability has been resolved: net: dsa: mv88e6xxx: avoid unregistering devlink regions which were never registered Russell King reports that a system with mv88e6xxx dereferences a NULL pointer when unbinding this driver: https://lore.kernel.org/netdev/Z_lRkMlTJ1KQ0kVX@shell.armlinux.org.uk/ The crash seems to be in devlink_region_destroy(), which is not NULL tolerant but is given a NULL devlink global region pointer. At least on some chips, some devlink regions are conditionally registered since the blamed commit, see mv88e6xxx_setup_devlink_regions_global(): if (cond && !cond(chip)) continue; These are MV88E6XXX_REGION_STU and MV88E6XXX_REGION_PVT. If the chip does not have an STU or PVT, it should crash like this. To fix the issue, avoid unregistering those regions which are NULL, i.e. were skipped at mv88e6xxx_setup_devlink_regions_global() time.

Affected products

Linux kernel: from 5.13 before 5.15.181; from 5.16 before 6.1.135; from 6.2 before 6.6.88; from 6.7 before 6.12.25; from 6.13 before 6.14.4; 6.15-rc1, 6.15-rc2 — fixed in 5.15.181, 6.1.135, 6.12.25, 6.14.4, 6.6.88

How to fix

Upgrade to a fixed version: Linux kernel 5.15.181, 6.1.135, 6.12.25, 6.14.4. Check the vendor advisory for mitigations.

References

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