CVE-2026-115918
Description
A flaw was found in vLLM. This vulnerability allows an authenticated remote attacker to cause a Denial of Service (DoS) by submitting a request containing an untrusted chat template to the responses endpoint. When no server template is configured, the application fails to enforce template trust restrictions and directly processes the user-supplied template. Rendering this untrusted template leads to excessive processor and memory consumption, exhausting system resources and making the serving engine unresponsive.
Statement
This vulnerability is rated as having a Moderate impact because exploitation is restricted to resource exhaustion and service disruption, without enabling arbitrary code execution or compromising data confidentiality and integrity. Within Red Hat OpenShift AI and Red Hat Enterprise Linux AI, the issue affects model-serving environments running vLLM when an explicit server-side chat template is omitted from the configuration. An authenticated user must have network access to invoke the responses API endpoint to trigger template rendering that consumes excessive CPU cycles and memory.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.5 | N/A | 6.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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