Linux Kernel up to 7.3.0 Histograms event_hist_trigger_parse/hist_unreg_all event_call/ref use after free

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8.1	$0-$5k	1.20

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.3.0. It has been rated as very critical. The affected element is the function event_hist_trigger_parse/hist_unreg_all of the component Histograms. This manipulation of the argument event_call/ref causes use after free. The identification of this vulnerability is CVE-2026-99233. The attack can only be executed locally. There is no exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Linux Kernel up to 7.3.0. It has been declared as very critical. Affected by this vulnerability is the function event_hist_trigger_parse/hist_unreg_all of the component Histograms. The manipulation of the argument event_call/ref with an unknown input leads to a use after free vulnerability. The CWE definition for the vulnerability is CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at git.kernel.org. This vulnerability is known as CVE-2026-99233 since 09/25/2026. The exploitation appears to be easy. Attacking locally is a requirement. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 11/02/2026).

Upgrading to version 6.1.191, 6.6.161, 6.12.115, 6.18.60, 7.2.14 or 7.3.1 eliminates this vulnerability. Applying the patch 381f543ed35c434d5b707369aa5dcd69ecf440af/4472579bd1c83708b6fe623c870cdf728e947205/23b4106e8b35823acc79e206c7745f55b9cfd78b/06e816bed499fe47f39f12044382cc5d064485fb/5597bb8db6855fcb97a67196d227fea359bcd81c/cf4e31d5da80fae4c9cdbe7af55b7c3ad213f0e4 is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-115275). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.1.190
• 6.6.160
• 6.12.114
• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.18.7
• 6.18.8
• 6.18.9
• 6.18.10
• 6.18.11
• 6.18.12
• 6.18.13
• 6.18.14
• 6.18.15
• 6.18.16
• 6.18.17
• 6.18.18
• 6.18.19
• 6.18.20
• 6.18.21
• 6.18.22
• 6.18.23
• 6.18.24
• 6.18.25
• 6.18.26
• 6.18.27
• 6.18.28
• 6.18.29
• 6.18.30
• 6.18.31
• 6.18.32
• 6.18.33
• 6.18.34
• 6.18.35
• 6.18.36
• 6.18.37
• 6.18.38
• 6.18.39
• 6.18.40
• 6.18.41
• 6.18.42
• 6.18.43
• 6.18.44
• 6.18.45
• 6.18.46
• 6.18.47
• 6.18.48
• 6.18.49
• 6.18.50
• 6.18.51
• 6.18.52
• 6.18.53
• 6.18.54
• 6.18.55
• 6.18.56
• 6.18.57
• 6.18.58
• 6.18.59
• 7.0
• 7.1
• 7.2
• 7.2.0
• 7.2.1
• 7.2.2
• 7.2.3
• 7.2.4
• 7.2.5
• 7.2.6
• 7.2.7
• 7.2.8
• 7.2.9
• 7.2.10
• 7.2.11
• 7.2.12
• 7.2.13
• 7.3.0

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.3
VulDB Meta Temp Score: 8.1

VulDB Base Score: 8.8
VulDB Temp Score: 8.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.8
CNA Vector (Linux): 🔒

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.1.191/6.6.161/6.12.115/6.18.60/7.2.14/7.3.1
Patch: 381f543ed35c434d5b707369aa5dcd69ecf440af/4472579bd1c83708b6fe623c870cdf728e947205/23b4106e8b35823acc79e206c7745f55b9cfd78b/06e816bed499fe47f39f12044382cc5d064485fb/5597bb8db6855fcb97a67196d227fea359bcd81c/cf4e31d5da80fae4c9cdbe7af55b7c3ad213f0e4

Timelineinfo

09/25/2026 CVE reserved
11/02/2026 +38 days Advisory disclosed
11/02/2026 +0 days VulDB entry created
11/02/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CNA: Linux
CVE: CVE-2026-99233 (🔒)

GCVE (CVE): GCVE-0-2026-99233
GCVE (VulDB): GCVE-100-429919
EUVD: 🔒

Entryinfo

Created: 11/02/2026 17:27
Updated: 11/02/2026 18:42
Changes: 11/02/2026 17:27 (69), 11/02/2026 18:42 (1)
Complete: 🔍
Cache ID: 216::103

Be aware that VulDB is the high quality source for vulnerability data.

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