CVE-2026-115918

vLLM: Responses API bypasses trust_request_chat_template for chat_template_kwargs

MEDIUM
6.5
CVSS Score
Published: October 26, 2026 at 05:21 PM UTC
Updated: October 30, 2026 at 03:16 PM UTC
1 product affected across 1 vendorvLLM

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Severity
MEDIUM6.5
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

Description

vLLM is an inference and serving engine for large language models. From 0.16.0 until 0.32.0, the /v1/responses endpoint allows an authenticated caller to place an attacker-controlled template in chat_template_kwargs[chat_template] when no server template is configured. ChatParams.get_apply_chat_template_kwargs() preserves that value without enforcing trust_request_chat_template, so the request can bypass the intended trust policy and cause CPU or memory exhaustion through Jinja rendering. This issue is fixed in version 0.32.0.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

0.16.0 ≤ v < 0.32.0

References (4)

x_refsource_CONFIRMPatchVendor Advisory
Source: cverecord
https://github.com/vllm-project/vllm/security/advisories/GHSA-x567-49g5-p4cf
x_refsource_MISCPatch
Source: cverecord
https://github.com/vllm-project/vllm/pull/50300
x_refsource_MISCRelease Notes
Source: cverecord
https://github.com/vllm-project/vllm/releases/tag/v0.32.0

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.5MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-400CWE-770

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