VDB-177850 · CVE-2021-36087 · Nessus 209513

SELinux 3.2 CIL Compiler ebitmap_match_any heap-based overflow

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.
4.3	$0-$5k	0.00

Summaryinfo

A vulnerability categorized as critical has been discovered in SELinux 3.2. This affects the function ebitmap_match_any of the component CIL Compiler. Executing a manipulation can lead to heap-based overflow. This vulnerability is registered as CVE-2021-36087. No exploit is available. A patch should be applied to remediate this issue.

Detailsinfo

A vulnerability classified as critical was found in SELinux 3.2. This vulnerability affects the function ebitmap_match_any of the component CIL Compiler. The manipulation with an unknown input leads to a heap-based overflow vulnerability. The CWE definition for the vulnerability is CWE-122. A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc(). As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

The CIL compiler in SELinux 3.2 has a heap-based buffer over-read in ebitmap_match_any (called indirectly from cil_check_neverallow). This occurs because there is sometimes a lack of checks for invalid statements in an optional block.

The weakness was published 07/01/2021. The advisory is available at bugs.chromium.org. This vulnerability was named CVE-2021-36087. Technical details are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 209513 (Debian dla-3930 : libsepol1 - security update), which helps to determine the existence of the flaw in a target environment.

Applying a patch is able to eliminate this problem. The bugfix is ready for download at github.com.

The vulnerability is also documented in the vulnerability database at Tenable (209513). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Name

SELinux

Version

License

open-source

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.4
VulDB Meta Temp Score: 4.3

VulDB Base Score: 5.5
VulDB Temp Score: 5.3
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 3.3
NVD Vector: 🔍

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: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Heap-based overflow
CWE: CWE-122 / CWE-119
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: Partially

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: 209513
Nessus Name: Debian dla-3930 : libsepol1 - security update

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Patch
Status: 🔍

0-Day Time: 🔍

Patch: github.com

Timelineinfo

07/01/2021 🔍
07/01/2021 +0 days 🔍
07/01/2021 +0 days 🔍
11/04/2025 +1587 days 🔍

Sourcesinfo

Advisory: bugs.chromium.org
Status: Confirmed

CVE: CVE-2021-36087 (🔍)
GCVE (CVE): GCVE-0-2021-36087
GCVE (VulDB): GCVE-100-177850
scip Labs: https://www.scip.ch/en/?labs.20140109

Entryinfo

Created: 07/01/2021 07:41
Updated: 11/04/2025 05:42
Changes: 07/01/2021 07:41 (38), 07/04/2021 16:41 (5), 10/22/2024 15:04 (16), 11/04/2025 05:42 (20)
Complete: 🔍
Cache ID: 216::103

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