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TI-2026-80500 Aliases CVE-2026-115911GHSA-542m-9234-8gvf

Denial of service via unbounded chat template rendering in vLLM

Priority LOW 29CWE-400Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Partial Red Hat: 3 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-400.

Summary

vLLM from 0.19.0 before 0.32.0 renders chat templates without a wall-clock timeout, output size limit or iteration bound (CWE-400). An authenticated caller can supply a request chat template when the server has none configured, and a malicious model repository can supply one too. A template that never terminates can block /v1/responses and other chat template users, and a template that expands its output can exhaust server memory. Harmony models are not affected.

Written with Claude Haiku 5.5 from the sources below · 2026-10-30

Description from the CNA

vLLM is an inference and serving engine for large language models. From 0.19.0 until 0.32.0, authenticated callers can supply a request chat template when no server-side --chat-template is configured, or a malicious model repository can provide a template that is compiled and rendered by tokenizer.apply_chat_template() without a wall-clock timeout, output-size limit, or iteration bound. Rendering runs in a ThreadPoolExecutor with one worker by default, so a nonterminating render can block /v1/responses and other chat-template users after the request ends, while an output-expanding render can exhaust server memory. Harmony models are not affected because they do not use this Jinja path. This issue is fixed in version 0.32.0.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00312 24th percentileScored 2026-11-07
Fix Partial vllm (vllm-project): 0.32.0vllm (PyPI): 0.32.0Red Hat: 3 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
vllm-projectvllm0.19.0 to before 0.32.00.32.0Patch availableCNA
—vllm (PyPI)0.19.0 to before 0.32.00.32.0Patch availableGHSA-542m-9234-8gvf
  • vllm Vendorvllm-project Affected 0.19.0 to before 0.32.0 Fixed in 0.32.0 Patch available CNA
  • vllm (PyPI) Vendor— Affected 0.19.0 to before 0.32.0 Fixed in 0.32.0 Patch available GHSA-542m-9234-8gvf

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:vllm:vllm:*:*:*:*:*:*:*:*0.19.0 to before 0.32.0VulnerablevLLM
  • cpe:2.3:a:vllm:vllm:*:*:*:*:*:*:*:* Versions 0.19.0 to before 0.32.0 Vulnerable ·vLLM

Remediation

Upgrade the vllm package from PyPI to 0.32.0, which fixes this flaw. Red Hat AI Inference Server, Red Hat Enterprise Linux AI (RHEL AI) 3 and Red Hat OpenShift AI (RHOAI) are affected, and Red Hat's plan for each is none available.

Written with Claude Haiku 5.5 from the sources below · 2026-10-30

  • Fix · CNA vllm (vllm-project) Fixed in 0.32.0
  • Fix · GHSA-542m-9234-8gvf vllm (PyPI) Fixed in 0.32.0 Advisory →

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat AI Inference ServerAffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux AI (RHEL AI) 3AffectedNo fix yet: Fix deferred
Red Hat OpenShift AI (RHOAI)AffectedNo fix yet: Fix deferred

Timeline

  1. 2026-10-26 Threatist record created from CVE-2026-115911
  2. 2026-10-27 Affected versions changed · Red Hat
  3. 2026-10-27 CVSS score added · Red Hat
  4. 2026-10-27 Priority changed: MEDIUM → LOW
  5. 2026-10-28 Alias added: GHSA-542m-9234-8gvf
  6. 2026-10-28 Fix available: PyPI/[email protected] · GHSA-542m-9234-8gvf
  7. 2026-10-28 CVSS score added · GHSA-542m-9234-8gvf
  8. 2026-10-28 Weakness changed · GHSA-542m-9234-8gvf
  9. 2026-10-28 6 new references · GHSA-542m-9234-8gvf
  10. 2026-10-30 CISA SSVC decision points changed

References

Patch 3

Advisory 1

Other 2

  • TI-2024-10229 Remote Code Execution in vllm-project/vllm CVSS 3.0CRITICAL 9.8
  • TI-2024-08404 Remote Code Execution in vllm-project/vllm CVSS 3.1CRITICAL 9.8
  • TI-2026-36017 vLLM: OpenAI auth bypass CVSS 3.1CRITICAL 9.1
  • TI-2026-63056 vLLM before 0.28.0 Denial of Service via negative token ID CVSS 4.0HIGH 8.7
  • TI-2026-04308 Hardcoded trust_remote_code=True in vllm-project/vllm Bypasses User Security Control CVSS 3.0HIGH 8.8
  • TI-2026-39137 vLLM: Remote DoS in vLLM via Invalid Recovered Token Reinjection CVSS 3.1HIGH 7.5
See all 124 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences