CVE-2026-99235: Linux Vulnerability (CVSS 7.8)

Description

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. 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.

Metrics

CVSS 3.1

7.8/10

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

EPSS Probability

0.12%

1.7th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= 02205a6752f223779a1b0e9e8ffacbea6e717851, < a6165126b1a1b26342b55be6eb6ee23af8756aba; >= 02205a6752f223779a1b0e9e8ffacbea6e717851, < 173914501b97236d7ea7dc2af7f30feddd4e1436; >= 02205a6752f223779a1b0e9e8ffacbea6e717851, < ac815a379644b2ad5008a009a3516ada31b5dd82; >= 02205a6752f223779a1b0e9e8ffacbea6e717851, < 8b307d64a60548e4a74cb746f74d7ed4bd49965e; >= 02205a6752f223779a1b0e9e8ffacbea6e717851, < 7a111ba0d1b74c99bc8f096565dc71945f694254; >= 02205a6752f223779a1b0e9e8ffacbea6e717851, < 3609ada3c12cecfb0ae5ee82ef4f86c5f18a2dea; >= 02205a6752f223779a1b0e9e8ffacbea6e717851, < 9631dbccd3c649b567a5aafffea6b00634183997; >= 02205a6752f223779a1b0e9e8ffacbea6e717851, < 7cafc82e6153f05a221be678cd649d02e06ba909; >= 02205a6752f223779a1b0e9e8ffacbea6e717851, < d5c42664fc094899af9aae5300b27fe8fdb658ef
Linux	Linux	4.17

References

Timeline

Published: Nov 2, 2026
Last Modified: Nov 3, 2026
Status: Received

Frequently Asked Questions

What is CVE-2026-99235?

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. 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.

How severe is CVE-2026-99235?

CVE-2026-99235 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.12% probability of exploitation in the next 30 days.

How do I fix CVE-2026-99235?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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