إرسال #956250: vLLM Project vLLM v0.26.0 Denial of Service

vLLM's Rust-based Gemma4UnifiedParser contains an uncontrolled recursion vulnerability when parsing nested tool-call arguments. The parser implements Gemma4's object and array grammar using mutually recursive parsing functions without enforcing a maximum nesting depth.

A sufficiently deeply nested tool-call argument can exhaust the stack of the worker thread performing the parse. In Rust, stack overflow results in a fatal runtime error and process abort rather than a recoverable parser error or ordinary panic. Consequently, triggering the vulnerable parser can terminate the vLLM serving process and cause denial of service.

The parser processes model-generated tool-call output. An attacker who can submit prompts to a vLLM deployment can attempt to cause the model to emit the nested structure required to exercise the vulnerable parser.

Once sufficient nesting reaches the parser, stack exhaustion causes a fatal Rust runtime abort. This is not limited to returning a parser error for the malicious request: the process executing the parser terminates.

Therefore, an attacker capable of influencing generated tool-call output may be able to terminate an affected vLLM serving process and disrupt availability for other users of that process.

The exploit requires:

A vLLM deployment using the affected Gemma4 unified parser.
The attacker being able to submit inference requests.
The attacker successfully steering model output toward a sufficiently deeply nested Gemma4 tool-call argument.

Fix

The issue was fixed by vLLM PR #54303:

https://github.com/vllm-project/vllm/pull/54303

• المصدر: ⚠️ https://github.com/vllm-project/vllm/issues/50927
• المستخدم: Zyz3366 (UID 97230)
• ارسال: 02/09/2026 12:19 AM (29 أيام منذ)
• الاعتدال: 30/09/2026 12:37 PM (29 days later)
• الحالة: تمت الموافقة
• إدخال VulDB: 411965 [vllm-project vLLM حتى 0.26.0 Gemma4UnifiedParser gemma4.rs الحرمان من الخدمة]
• النقاط: 20