What’s Vulnerable › Vulnerabilities

CVE-2025-39872: hsr: hold rcu and dev lock for hsr_get_port_ndev

• 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: 2025-09-23 · updated 2026-10-19

Description

In the Linux kernel, the following vulnerability has been resolved: hsr: hold rcu and dev lock for hsr_get_port_ndev hsr_get_port_ndev calls hsr_for_each_port, which need to hold rcu lock. On the other hand, before return the port device, we need to hold the device reference to avoid UaF in the caller function.

Affected products

• Linux kernel: from 6.14 before 6.16.8; 6.17-rc1, 6.17-rc2, 6.17-rc3, 6.17-rc4, 6.17-rc5 — fixed in 6.16.8

How to fix

Upgrade to a fixed version: Linux kernel 6.16.8. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/68a6729afd3e8e9a2a32538642ce92b96ccf9b1d
• https://git.kernel.org/stable/c/847748fc66d08a89135a74e29362a66ba4e3ab15
• https://git.kernel.org/stable/c/9433ba79c2ec3ec7c9a711748701549339c3438c

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