Live › vulnerability › CVE-2026-98540
Go to dashboardIn the Linux kernel's fprobe tracing code, the return path can read leftover data from an unused slot, so an exit handler may run twice or run after its entry handler asked to skip it. The sources do not describe a direct way for an attacker to gain code execution or read data.
Summary written from the sources below. Check the originals before acting.
First seen by InfraStack 2026-10-23 21:57 UTC. All times on this page are UTC.
Systems running a Linux kernel build that includes the fprobe and function graph tracing code with the affected fprobe exit handlers. Exposure depends on whether fprobe tracing is used on the machine; the sources do not say who can trigger it. Teams on unaffected kernel versions or without fprobe usage can skip it.
No product ranges from the sources yet.
Each row is the first time that source carried this signal. The analyst’s rows are its own findings.
In the Linux kernel, the following vulnerability has been resolved:
fprobe: Terminate the fgraph_data list when the reservation is not filled
fprobe_fgraph_entry() reserves shadow stack space for every fprobe with an exit handler, but only fills it for those whose entry handler returns 0. fgraph_reserve_data() does not clear the area, so fprobe_return() parses the unused tail as headers left over from an earlier call, and an exit handler can run twice or despite its entry handler asking to skip it.
Write a zero word after the last entry to terminate the walk. A zeroed slot does not decode to a NULL fprobe on the arches that encode the header into one unsigned long, since arch_decode_fprobe_header_fp() ORs in FPROBE_HEADER_MSB_PATTERN, so make read_fprobe_header() return NULL for a zeroed slot.
This page as .md · .json · in your agent: get_signal("CVE-2026-98540")
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