CVE-2021-32795

Denial of Service via Steam chat in ArchiSteamFarm

MEDIUM
5.9
CVSS Score
Published: July 26, 2021 at 07:25 PM UTC
Updated: June 17, 2026 at 03:53 AM UTC
2 products affected across 2 vendorsArchisteamfarmArchiSteamFarm

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Severity
MEDIUM5.9
Exploit prediction
EPSS 2%

Description

ArchiSteamFarm is a C# application with primary purpose of idling Steam cards from multiple accounts simultaneously. In versions prior to 4.3.1.0 a Denial of Service (aka DoS) vulnerability which allows attacker to remotely crash running ASF instance through sending a specifically-crafted Steam chat message exists. The user sending the message does not need to be authorized within the bot or ASF process. The attacker needs to know ASF's `CommandPrefix` in advance, but majority of ASF setups run with an unchanged default value. This attack does not allow attacker to gain any potentially-sensitive information, such as logins or passwords, does not allow to execute arbitrary commands and otherwise exploit the crash further. The issue is patched in ASF V4.3.1.0. The only workaround which guarantees complete protection is running all bots with `OnlineStatus` of `0` (Offline). In this setup, ASF is able to ignore even the specifically-crafted message without attempting to interpret it.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 4.3.1.0
Affected range stops below 4.3.1.0, so it looks safe — our inference, not a vendor statement
v < 4.3.1.0
Affected range stops below 4.3.1.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

CVSS

Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-20

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