CVE-2026-23206: dpaa2-switch: prevent ZERO_SIZE_PTR dereference when num_ifs is zero

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-02-14 · updated 2026-06-17
Weakness: CWE-476

Description

In the Linux kernel, the following vulnerability has been resolved: dpaa2-switch: prevent ZERO_SIZE_PTR dereference when num_ifs is zero The driver allocates arrays for ports, FDBs, and filter blocks using kcalloc() with ethsw->sw_attr.num_ifs as the element count. When the device reports zero interfaces (either due to hardware configuration or firmware issues), kcalloc(0, ...) returns ZERO_SIZE_PTR (0x10) instead of NULL. Later in dpaa2_switch_probe(), the NAPI initialization unconditionally accesses ethsw->ports[0]->netdev, which attempts to dereference ZERO_SIZE_PTR (address 0x10), resulting in a kernel panic. Add a check to ensure num_ifs is greater than zero after retrieving device attributes. This prevents the zero-sized allocations and subsequent invalid pointer dereference.

Affected products

Linux kernel: from 5.13 before 5.15.200; from 5.16 before 6.1.163; from 6.2 before 6.6.124; from 6.7 before 6.12.70; from 6.13 before 6.18.10; 6.19-rc1, 6.19-rc2, 6.19-rc3, 6.19-rc4, 6.19-rc5, 6.19-rc6 (+2) — fixed in 5.15.200, 6.1.163, 6.12.70, 6.18.10, 6.6.124

How to fix

Upgrade to a fixed version: Linux kernel 5.15.200, 6.1.163, 6.12.70, 6.18.10. Check the vendor advisory for mitigations.

References

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