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Fencer Vulns
high 7.8

CVE-2026-99235 json

tracing: Save the event file instead of the compatible histogram

published 2026-11-02 6 d ago modified 2026-11-03 5 d ago also EUVD-2026-115277

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 2%
public exploits
0
none known

Summary

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.

Patch / fix

  • Linux Linux 5.10.273, 5.15.224, 6.1.191, 6.6.161, 6.12.115, 6.18.60, 7.2.14, 7.3.1, 7.4-rc1
  • linux Debian 13 6.12.115-1
  • linux Debian 14 7.2.14-1

debian advisories DEBIAN-CVE-2026-99235

  • kernel Azure Linux 3.0 6.6.161.1-1

azure linux advisories AZL-112571

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-99235 updated cvss 7.8

kernel: kernel: Privilege escalation via use-after-free in event tracing subsystem

  • Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat Enterprise Linux 10 kernel Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9 Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9, openshift/ose-rhel-coreos-10
    affected: workaround, no fix available
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.12% chance of exploitation in the next 30 days, higher than 2% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

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