grub2 up to 2.11 16-bit Grayscale PNG Image out-of-bounds write

CVSS Meta Temp Score
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CTI Interest Score
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5.7$0-$5k0.00

Summaryinfo

A vulnerability classified as critical was found in grub2 up to 2.11. This affects an unknown function of the component 16-bit Grayscale PNG Image Handler. Executing a manipulation can lead to out-of-bounds write. This vulnerability is handled as CVE-2021-3695. There is not any exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability classified as critical was found in grub2 up to 2.11. This vulnerability affects an unknown function of the component 16-bit Grayscale PNG Image Handler. The manipulation with an unknown input leads to a out-of-bounds write vulnerability. The CWE definition for the vulnerability is CWE-787. The product writes data past the end, or before the beginning, of the intended buffer. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

A crafted 16-bit grayscale PNG image may lead to a out-of-bounds write in the heap area. An attacker may take advantage of that to cause heap data corruption or eventually arbitrary code execution and circumvent secure boot protections. This issue has a high complexity to be exploited as an attacker needs to perform some triage over the heap layout to achieve signifcant results, also the values written into the memory are repeated three times in a row making difficult to produce valid payloads. This flaw affects grub2 versions prior grub-2.12.

The weakness was released 07/06/2022. The advisory is available at bugzilla.redhat.com. This vulnerability was named CVE-2021-3695 since 08/10/2021. The technical details are unknown and an exploit is not 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.

Upgrading to version 2.12 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (236637). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.8
VulDB Meta Temp Score: 5.7

VulDB Base Score: 7.1
VulDB Temp Score: 6.8
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 4.5
NVD Vector: 🔍

CVSSv2info

AVACAuCIA
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Out-of-bounds write
CWE: CWE-787 / CWE-119
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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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: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: grub2 2.12

Timelineinfo

08/10/2021 🔍
07/06/2022 +330 days 🔍
07/06/2022 +0 days 🔍
05/19/2025 +1048 days 🔍

Sourcesinfo

Advisory: bugzilla.redhat.com
Status: Confirmed

CVE: CVE-2021-3695 (🔍)
GCVE (CVE): GCVE-0-2021-3695
GCVE (VulDB): GCVE-100-203266

Entryinfo

Created: 07/06/2022 21:17
Updated: 05/19/2025 19:40
Changes: 07/06/2022 21:17 (39), 07/19/2022 12:17 (18), 05/19/2025 19:40 (16)
Complete: 🔍
Cache ID: 216::103

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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