CVE intelligence

CVE-2026-99233

Vulnerability intelligence

Published Nov 2, 2026Sources checked Nov 5, 2026

7.8HIGHCVSS out of 10

What this means

Review the available evidence

CVE-2026-99233 and is rated High severity with a CVSS score of 7.8. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

What to do next

Remediation and response

Microsoft Security Response Center guidance

Vendor revision: Nov 4, 2026

Release Notes

CISA KEVNot listedBased on the latest collected catalog

EPSS0.1%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-99233?

In the Linux kernel, the following vulnerability has been resolved:

tracing/histograms: Verify event_call identity when updating synth_event refcount

In event_hist_trigger_parse() and hist_unreg_all(), the histogram registration and unregistration paths look up find_synth_event() using trace_event_name(file->event_call) and adjust se->ref if a match is found.

Because find_synth_event() only compares the event basename, registering or removing a histogram on a non-synthetic trace event whose basename matches a synthetic event erroneously modifies the synthetic event's reference count.

If a histogram is registered on the non-synthetic event before the synthetic event is created and removed afterwards, se->ref is decremented without a matching increment, allowing the synthetic event to be freed while an active histogram action still holds a pointer to it.

Introduce find_synth_event_call() to verify that &se->call matches file->event_call before adjusting se->ref.

Source: NVD