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Response snapshot Nov 2, 2026, 17:11 UTC

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VulnerabilityCVE-2026-99235

Linux kernel: tracing: Save the event file instead of the compatible histogram

In the Linux kernel, the following vulnerability has been resolved: tracing: Save the event file instead of the compatible histogram create_field_var_hist() creates a histogram on the matched event to supply a field variable, and records it on the target so it can be torn down later: hist_data = find_compatible_hist(target_hist_data, file); ...

At a glance

Exploited
Not known
Severity
7.8 High (CVSS 3.1)
Chance of exploitation
Not estimated
Sources
1 source

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2026-99235 (opens a new tab)

What happened

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

tracing: Save the event file instead of the compatible histogram

create_field_var_hist() creates a histogram on the matched event to supply a field variable, and records it on the target so it can be torn down later:

hist_data = find_compatible_hist(target_hist_data, file); ... /* Save the compatible histogram information */ var_hist->hist_data = hist_data;

Continue reading

hist_data is not the histogram it creates. It is one that was already there, whose keys the new one copies. The saved pointer has a single user, unregister_field_var_hists(), which runs when the target is removed:

file = hist_data->field_var_hists[i]->hist_data->event_file;

find_compatible_hist() matches on keys alone, so it can pick one with no variables of its own. check_var_refs() then returns false and the user can remove it while the target still points at it:

BUG: KASAN: slab-use-after-free in event_hist_trigger_free+0x2b2/0x320 Read of size 8 at addr ffff8880093b90e0 by task init/1

Freed by task 1: kfree+0x154/0x420 event_hist_trigger_free+0x1d5/0x320 event_hist_trigger_parse+0x35f3/0x69e0 trigger_process_regex+0x1a6/0x250

Save the event file instead. It is all the dereference ever wanted, and it does not go away when the user removes a trigger.

Scores and how they were measured

CVSS base severity

7.8

Version 3.1As of

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

Not available

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    NVD CVE-2026-99235 (opens a new tab)

    NVD record: description, CVSS (the CNA score is preferred), affected products, and publication date. Not evidence of exploitation.

    Published Checked

  2. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  3. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, November 2). Linux kernel: tracing: Save the event file instead of the compatible histogram (CVE-2026-99235). https://kevwire.com/record/CVE-2026-99235

MLA

"Linux kernel: tracing: Save the event file instead of the compatible histogram (CVE-2026-99235)." KEVWire, 2 Nov. 2026, kevwire.com/record/CVE-2026-99235.

Chicago

KEVWire. "Linux kernel: tracing: Save the event file instead of the compatible histogram (CVE-2026-99235)." Last modified November 2, 2026. https://kevwire.com/record/CVE-2026-99235.

Evidence summary (plain text)

Linux kernel: tracing: Save the event file instead of the compatible histogram (Nov 2, 2026).
In the Linux kernel, the following vulnerability has been resolved:

tracing: Save the event file instead of the compatible histogram

create_field_var_hist() creates a histogram on the matched event to
supply a field variable, and records it on the target so it can be torn
down later:

	hist_data = find_compatible_hist(target_hist_data, file);
	...
	/* Save the compatible histogram information */
	var_hist->hist_data = hist_data;

hist_data is not the histogram it creates. It is one that was already
there, whose keys the new one copies.
CVSS 7.8 (version 3.1; evidence as of Nov 2, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-99235).
Sources:
NVD CVE-2026-99235: https://nvd.nist.gov/vuln/detail/CVE-2026-99235
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-02T15:36:06.356Z&lastModEndDate=2026-11-02T17:10:56.063Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-02T15:01:12.608Z&lastModEndDate=2026-11-02T16:35:57.586Z&resultsPerPage=500&startIndex=500
Record ID: CVE-2026-99235.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Nov 2, 2026, 17:10 UTC. Ingestion is not an independent editorial investigation.

NVD status: Received. Publication in the NVD is not evidence of exploitation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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Record details

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