CVE-2025-23155: net: stmmac: Fix accessing freed irq affinity_hint

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 2026-07-30

Description

In the Linux kernel, the following vulnerability has been resolved: net: stmmac: Fix accessing freed irq affinity_hint In stmmac_request_irq_multi_msi(), a pointer to the stack variable cpu_mask is passed to irq_set_affinity_hint(). This value is stored in irq_desc->affinity_hint, but once stmmac_request_irq_multi_msi() returns, the pointer becomes dangling. The affinity_hint is exposed via procfs with S_IRUGO permissions, allowing any unprivileged process to read it. Accessing this stale pointer can lead to: - a kernel oops or panic if the referenced memory has been released and unmapped, or - leakage of kernel data into userspace if the memory is re-used for other purposes. All platforms that use stmmac with PCI MSI (Intel, Loongson, etc) are affected.

Affected products

Linux kernel: from 5.13 before 6.12.36; from 6.13 before 6.13.12; from 6.14 before 6.14.3 — fixed in 6.12.36, 6.13.12, 6.14.3

How to fix

Upgrade to a fixed version: Linux kernel 6.12.36, 6.13.12, 6.14.3. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2025-23155 or the next vulnerability affects your stack