CVE-2026-98076 Linux CVE debrief

Who should care

Linux kernel developers and maintainers, Linux distribution maintainers, and users of Linux-based systems who use tracing/probes functionality. These stakeholders should assess exposure and prioritize patching or mitigation due to the potential for system crashes, unexpected behavior, or security issues.

Why it matters

A use-after-free vulnerability in the Linux kernel's tracing/probes functionality can lead to potential system crashes, unexpected behavior, or security issues. Linux kernel developers, maintainers, and users of Linux-based systems who use tracing/probes functionality should assess exposure and prioritize patching or mitigation.

• Potential system crashes or unexpected behavior due to use-after-free vulnerability
• Possible elevation of privileges or denial of service (DoS) attacks
• Need for thorough testing and validation of Linux kernel versions and patches
• Importance of monitoring system logs for potential exploitation attempts or crashes

Technical summary

The fields of a probe-based dynamic event (kprobe, uprobe, eprobe and fprobe events) are created in traceprobe_define_arg_fields() by handing the probe_arg name/type strings to trace_define_field(), which only stores the pointers without copying. Those strings are owned by the trace_probe and are freed when that probe is removed. An event can have several probes attached. The field list is defined only once, by the first probe that registers the event, but it is kept alive by any surviving sibling probe.

Defensive priority

Medium

Recommended defensive actions

• Review and apply the provided kernel patches to fix the vulnerability
• Ensure that all Linux kernel versions in use are up-to-date with the latest security patches
• Monitor system logs for potential exploitation attempts or crashes related to the tracing/probes functionality
• Perform thorough testing and validation of Linux kernel versions and patches
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented.

Evidence notes

The issue was found by the autokbug dynamic kernel fuzzer at Tencent Yunding Lab. A reproducer was provided that reliably triggers the bug. The vulnerability arises from the handling of probe_arg name/type strings in traceprobe_define_arg_fields(). These strings are owned by the trace_probe and are freed when that probe is removed. The event's fields are created by handing these strings to trace_define_field(), which only stores the pointers without copying. To verify, defenders should review the official advisory or CVE record to

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.