Vulnerability identifier: #VU52200

Vulnerability risk: High

CVSSv3.1: 8.3 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:P/RL:U/RC:C]

CVE-ID: CVE-2021-30481

CWE-ID: CWE-119

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
Steam
Client/Desktop applications / Other client software

Vendor: Valve Software

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a boundary error when processing Steam invites. A remote attacker can send a specially crafted invite, trigger a buffer overflow after the user clicks on the invite, and execute arbitrary code on the system.

Mitigation
Cybersecurity Help is currently unaware of any official solution to address this vulnerability.

Vulnerable software versions

Steam: All versions

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External links
http://news.ycombinator.com/item?id=26762170
http://twitter.com/floesen_/status/1337107178096881666
http://twitter.com/the_secret_club/status/1380868759129296900
http://www.youtube.com/watch?v=rNQn--9xR1Q

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.