CVE-2026-115911
Description
A flaw was found in vLLM. An authenticated remote attacker or a malicious model repository can cause a Denial of Service (DoS) by providing a specially crafted chat template. Because templates are rendered without execution timeouts or resource limits, processing the input can permanently block worker threads or exhaust system memory, rendering the service unresponsive or causing it to crash.
Statement
This vulnerability is evaluated with a Moderate severity impact because successful exploitation results in service unavailability without compromising confidentiality or integrity, and it requires authenticated API access or the deployment of an untrusted model repository. In Red Hat OpenShift AI and Red Hat Enterprise Linux AI, the vLLM engine renders chat formatting templates without enforcing iteration or memory boundaries. While Jinja2 sandboxing prevents arbitrary code execution, exhausting the single-worker rendering thread pool or triggering out-of-memory errors disrupts inference requests across the specific serving instance. The blast radius is confined to the affected container replica, and underlying host infrastructure remains protected by container isolation.
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
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
