Vulnerability · Published Sep 26, 2026 · Assigned by VulnCheck

CVE-2026-100654vLLM before 0.29.0 Denial of Service via out-of-range stop_token_ids

Medium 6.5

In plain English

A medium-severity security flaw in vllm from vllm-project. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 24% of all known vulnerabilities).

Severity (CVSS 3.1)6.5Medium

Exploit odds (30 days)0.3%top 75.6% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

vLLM before 0.29.0 accepts user-controlled stop_token_ids on the OpenAI-compatible POST /v1/completions and POST /v1/chat/completions endpoints but validates only that the values are integers, not that each token id is within the model vocabulary/logits range. When min_tokens > 0, the stop token ids are used as logits indices to suppress stop tokens, so an out-of-range id reaches a CUDA indexing operation (index_put_) and triggers a device-side assertion. An authenticated API user can send a single malformed completion request that returns 500 Internal Server Error and puts EngineCore into a fatal state, causing subsequent requests to fail until the service is restarted (denial of service).

Affected products (as reported)

Vendor	Product	Versions
vllm-project	vllm	0 – before 0.29.0

Weakness: CWE-129 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

References

GitHub Security Advisory (GHSA-v5gm-qgmv-gc6c) vendor-advisory
VulnCheck Advisory: vLLM before 0.29.0 Denial of Service via out-of-range stop_token_ids third-party-advisory