Vulnerability Details : CVE-2021-30481

Valve Steam through 2021-04-10, when a Source engine game is installed, allows remote authenticated users to execute arbitrary code because of a buffer overflow that occurs for a Steam invite after one click.

Vulnerability category: OverflowExecute code

Published 2021-04-10 19:15:12

Updated 2022-02-07 19:09:14

Source MITRE

View at NVD, CVE.org

Exploit prediction scoring system (EPSS) score for CVE-2021-30481

Probability of exploitation activity in the next 30 days: 5.22%

Percentile, the proportion of vulnerabilities that are scored at or less: ~ 92 % EPSS Score History EPSS FAQ

CVSS scores for CVE-2021-30481

Base Score	Base Severity	CVSS Vector	Exploitability Score	Impact Score	Source
6.0	MEDIUM	AV:N/AC:M/Au:S/C:P/I:P/A:P	6.8	6.4	nvd@nist.gov
Access Vector: Network Access Complexity: Medium Authentication: Single Confidentiality Impact: Partial Integrity Impact: Partial Availability Impact: Partial
8.0	HIGH	CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H	1.3	6.0	cve@mitre.org
Attack Vector: Network Attack Complexity: High Privileges Required: Low User Interaction: Required Scope: Changed Confidentiality: High Integrity: High Availability: High
9.0	CRITICAL	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H	2.3	6.0	nvd@nist.gov
Attack Vector: Network Attack Complexity: Low Privileges Required: Low User Interaction: Required Scope: Changed Confidentiality: High Integrity: High Availability: High

CWE ids for CVE-2021-30481

CWE-120 Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow.

Assigned by: nvd@nist.gov (Primary)

References for CVE-2021-30481

https://twitter.com/floesen_/status/1337107178096881666

Florian on Twitter: "Recently, I've seen some people complaining about long response times at bugbounty programs. Let's play a game, can you beat one of my "recent" gems? A wormable, single click RCE
Third Party Advisory
https://twitter.com/the_secret_club/status/1380868759129296900

secret club on Twitter: "Two years ago, secret club member @floesen_ reported a remote code execution flaw affecting all source engine games. It can be triggered through a Steam invite. This has yet t
Exploit;Third Party Advisory
https://news.ycombinator.com/item?id=26762170

Valve accused of ignoring existing RCE vulnerability in Source games for 2 years | Hacker News
Issue Tracking;Third Party Advisory
https://www.youtube.com/watch?v=rNQn--9xR1Q

Before you continue to YouTube
Exploit;Third Party Advisory

Products affected by CVE-2021-30481

Valvesoftware » Steam Client
Versions up to, including, (<=) 2021-04-10
cpe:2.3:a:valvesoftware:steam_client:*:*:*:*:*:*:*:*
Matching versions