# vLLM: DoS via unbounded chat_template Jinja2 rendering exhausts the renderer thread pool

Advisory record · `GHSA-542m-9234-8gvf`

- **Identifiers:** `GHSA-542m-9234-8gvf` · `CVE-2026-115911` · `PYSEC-2026-4344`
- **State:** Confirmed
- **Severity:** CVSS 6.5 Medium
- **Critical:** No
- **Weakness (CWE):** [CWE-400](https://cwe.mitre.org/data/definitions/400.html) · [CWE-770](https://cwe.mitre.org/data/definitions/770.html) · [CWE-834](https://cwe.mitre.org/data/definitions/834.html)
- **Tags:** [Denial of service](https://agentprime.io/advisories/tag/dos.md)
- **Published:** 28 Oct 2026
- **Updated:** 29 Oct 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 28 Oct 2026, 21:14 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `vllm` (PyPI): affected `>=0.19.0, <0.32.0`; fixed in `0.32.0`

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 6.5 Medium, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0031, the 24th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:07 UTC: First seen by agentprime
- 31 Oct 2026, 14:07 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-542m-9234-8gvf)

## Sources

- [GitHub Advisory Database: GHSA-542m-9234-8gvf](https://github.com/advisories/GHSA-542m-9234-8gvf)
- [OSV: GHSA-542m-9234-8gvf](https://osv.dev/vulnerability/GHSA-542m-9234-8gvf)
- <https://github.com/vllm-project/vllm/security/advisories/GHSA-542m-9234-8gvf>
- <https://nvd.nist.gov/vuln/detail/CVE-2026-115911>
- <https://github.com/vllm-project/vllm/pull/50300>
- <https://github.com/vllm-project/vllm/commit/cff08b461e086523cee8bba5bd3c66d302625134>
- <https://github.com/vllm-project/vllm>
- <https://github.com/vllm-project/vllm/releases/tag/v0.32.0>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-542m-9234-8gvf>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-542m-9234-8gvf/>. Everything for agents: <https://agentprime.io/llms.txt>.