VDB-235029 · CVE-2022-28735 · Nessus 236637

Grub2 Non-Kernel File shim_lock Local Privilege Escalation

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
7.0	$0-$5k	0.00

Summaryinfo

A vulnerability marked as critical has been reported in Grub2. This vulnerability affects the function shim_lock of the component Non-Kernel File Handler. Performing a manipulation results in an unknown weakness. This vulnerability is cataloged as CVE-2022-28735. The attack must be initiated from a local position. There is no exploit available. Applying a patch is the recommended action to fix this issue.

Detailsinfo

A vulnerability, which was classified as critical, was found in Grub2 (the affected version is unknown). This affects the function shim_lock of the component Non-Kernel File Handler. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

The GRUB2's shim_lock verifier allows non-kernel files to be loaded on shim-powered secure boot systems. Allowing such files to be loaded may lead to unverified code and modules to be loaded in GRUB2 breaking the secure boot trust-chain.

The weakness was shared 07/20/2023. The advisory is shared at openwall.com. This vulnerability is uniquely identified as CVE-2022-28735 since 04/05/2022. Technical details are known, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 236637 (Alibaba Cloud Linux 3 : 0164: grub2, mokutil, shim, and shim-unsigned-x64 (ALINUX3-SA-2022:0164)), which helps to determine the existence of the flaw in a target environment.

Applying a patch is able to eliminate this problem.

The vulnerability is also documented in the vulnerability database at Tenable (236637). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Name

Grub2

License

open-source

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.1
VulDB Meta Temp Score: 7.0

VulDB Base Score: 6.7
VulDB Temp Score: 6.4
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.8
NVD Vector: 🔍

CNA Base Score: 6.7
CNA Vector (Canonical Ltd.): 🔍

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: Local Privilege Escalation
CWE: Unknown
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: No

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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

Nessus ID: 236637
Nessus Name: Alibaba Cloud Linux 3 : 0164: grub2, mokutil, shim, and shim-unsigned-x64 (ALINUX3-SA-2022:0164)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Patch
Status: 🔍

0-Day Time: 🔍

Timelineinfo

04/05/2022 🔍
07/20/2023 +471 days 🔍
07/20/2023 +0 days 🔍
05/19/2025 +669 days 🔍

Sourcesinfo

Advisory: openwall.com
Status: Confirmed

CVE: CVE-2022-28735 (🔍)
GCVE (CVE): GCVE-0-2022-28735
GCVE (VulDB): GCVE-100-235029

Entryinfo

Created: 07/20/2023 08:48
Updated: 05/19/2025 19:40
Changes: 07/20/2023 08:48 (46), 08/15/2023 08:25 (11), 05/19/2025 19:40 (16)
Complete: 🔍
Cache ID: 216::103

If you want to get the best quality for vulnerability data then you always have to consider VulDB.