Resource exhaustion in vLLM - CVE-2026-115911
Published: November 9, 2026
Vulnerability identifier: #VU162988
CSH Severity: Low
CVSS v4: 7.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-115911
CWE-ID: CWE-400
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows an authenticated remote attacker to deny chat-style inference to every tenant of a vLLM API-server replica until restart.
The vulnerability exists due to unbounded Jinja2 chat-template rendering with a non-harmony model, the default single renderer worker, and no configured --chat-template override. An authenticated remote attacker can submit one crafted template through /v1/responses to occupy the renderer indefinitely and block subsequent chat requests.
Affected software
vLLM
How to mitigate CVE-2026-115911
Install security update from vendor's website.
vLLM - update to 0.32.0