CVE Catalog

CVE-2025-38704

HighCVSS 7.8
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.16%

5th percentile - higher than 5% of all known CVEs

Summary

In the Linux kernel, a vulnerability in the RCU NOCB mechanism was found where improper checking of the `nocb_cb_kthread` pointer can lead to invalid memory access. The issue occurs during CPU NOCB de-offload and re-offload when `rcuop` thread creation fails.

Risk Assessment

The risk involves potential system instability due to accessing an invalid kernel thread pointer, which could cause a kernel panic or unpredictable behavior.

Recommendation

Immediately update the Linux kernel to a version containing the fix (commit using `rdp->nocb_gp_kthread` instead of `rdp_gp->nocb_gp_kthread`). Monitor distributions for the patch release.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: rcu/nocb: Fix possible invalid rdp's->nocb_cb_kthread pointer access In the preparation stage of CPU online, if the corresponding the rdp's->nocb_cb_kthread does not exist, will be created, there is a situation where the rdp's rcuop kthreads creation fails, and then de-offload this CPU's rdp, does not assign this CPU's rdp->nocb_cb_kthread pointer, but this rdp's->nocb_gp_rdp and rdp's->rdp_gp->nocb_gp_kthread is still valid. This will cause the subsequent re-offload operation of this offline CPU, which will pass the conditional check and the kthread_unpark() will access invalid rdp's->nocb_cb_kthread pointer. This commit therefore use rdp's->nocb_gp_kthread instead of rdp_gp's->nocb_gp_kthread for safety check.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS