CVE-2026-90878 vllm-project vLLM Jinja Template Rendering completions resource consumption
Remote attackers can cause resource exhaustion in vLLM via malicious Jinja templates in chat completions, requiring a patch to mitigate.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-90878?
CVE-2026-90878 is a medium-severity denial of service vulnerability in vllm-project vLLM, published on 15 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
A vulnerability was determined in vllm-project vLLM up to 0.27.1. This affects an unknown part of the file /v1/chat/completions of the component Jinja Template Rendering. This manipulation of the argument chat_template causes resource consumption. The attack can be initiated remotely. The exploit has been publicly disclosed and may be utilized. The pull request to fix this issue awaits acceptance.
Which versions are affected by CVE-2026-90878?
How do I fix CVE-2026-90878?
No fix has been published for CVE-2026-90878 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-90878 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-90878 exists.
Sources
Also known as GHSA-2h9j-24rv-h4c7.