CVE-2026-107692 in War Thunder
Summary
by MITRE • 10/20/2026
The War Thunder game client transmits its authentication bearer token (auth_jwt) in the very first data packet after the TCP handshake, using only LZ4 compression rather than encryption. An attacker positioned on the network path can passively intercept and decompress this packet to reveal the plaintext JSON payload. This vulnerability allows for temporary authenticated impersonation, enabling an attacker to access game services and certain user data (such as email address and displayed phone number) as the affected user. While this allows for unauthorized access to gameplay, it does not facilitate full account takeover, as it cannot be used to modify account security settings, change passwords, bypass two-factor authentication for account management, or access financial information.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 10/20/2026
The vulnerability identified in the War Thunder game client represents a critical failure in transport layer security during the initial phase of session establishment. Specifically, the application transmits its authentication bearer token, known as auth_jwt, within the very first data packet following the completion of the TCP handshake. This transmission occurs without any form of encryption, relying solely on LZ4 compression to obfuscate the payload. While compression reduces bandwidth usage and improves latency, it provides no confidentiality guarantees against network-level adversaries. An attacker positioned in a passive position along the network path can intercept this initial packet using standard packet capture tools. Because the data is only compressed and not encrypted with protocols such as TLS or DTLS, the adversary can easily decompress the LZ4 stream to reveal the plaintext JSON payload containing the sensitive authentication token.
This architectural flaw leads directly to a severe confidentiality breach classified under CWE-319: Cleartext Transmission of Sensitive Information. The exposure of the bearer token allows for temporary authenticated impersonation of the affected user. Once an attacker possesses this valid JWT, they can inject it into subsequent requests to game services, effectively masquerading as the legitimate user without needing their password or other credentials. This capability aligns with ATT&CK technique T1539: Steal Web Session Cookie, although in this context, it involves stealing a JSON Web Token rather than a traditional HTTP cookie. The attacker gains access to specific game services and can retrieve certain pieces of personally identifiable information associated with the account, including the user's email address and displayed phone number.
The operational impact of this vulnerability is significant regarding privacy and potential social engineering attacks, but it is bounded in terms of full account compromise. While an adversary can impersonate the user to access gameplay features and view sensitive contact details, they cannot perform actions that require higher levels of authentication or security verification. Specifically, the stolen token does not grant permission to modify critical account security settings, change passwords, bypass two-factor authentication mechanisms for administrative changes, or access financial information linked to the account. This limitation suggests that while the immediate risk is unauthorized data exposure and gameplay impersonation, the long-term risk of permanent account takeover is mitigated by the application's internal separation of privileges between game session tokens and administrative management credentials.
To mitigate this vulnerability, the most effective remediation strategy is to enforce encryption for all client-server communications from the very first packet exchanged after connection establishment. Implementing Transport Layer Security (TLS) or a similar encrypted protocol would ensure that even if an attacker intercepts the initial handshake data, they cannot decompress or read the contents of the authentication token. Additionally, shortening the lifespan and scope of bearer tokens can reduce the window of opportunity for exploitation. If encryption is not feasible due to legacy constraints, implementing cryptographic signing with additional obfuscation layers beyond simple compression may provide a marginal increase in security, though it remains inferior to standard TLS implementation. Regular network traffic analysis during development should also be conducted to ensure that no sensitive data is transmitted over unencrypted channels at any stage of the connection lifecycle.