Read the docs
TI-2026-51646 Aliases CVE-2026-73556GHSA-48jh-3gj7-fg8v

Regular expression denial of service in vllm-project vllm

Priority MEDIUM 63CWE-1333Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · Low
Fix status
Partial Red Hat: 7 fixed, 3 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-1333.

Summary

vLLM is an inference and serving engine for large language models. Prior to 0.26.0, the structured_outputs.regex parameter in vllm/v1/structured_output/backend_lm_format_enforcer.py is passed to lmformatenforcer.RegexParser without compile_regex_with_timeout or validation in validate_structured_output_request_lm_format_enforcer, allowing an unauthenticated /v1/completions request against the lm-format-enforcer backend to consume a CPU core and stall the structured-output engine path with a catastrophic regular expression. This issue is fixed in version 0.26.0.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00515 44th percentileScored 2026-11-07
Fix Partial vllm (vllm-project): 0.26.0vllm (PyPI): 0.26.0Red Hat: 26 advisoriesRed Hat: 7 fixed, 3 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
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-projectvllmbefore 0.26.00.26.0Patch availableCNA
—vllm (PyPI)before 0.26.00.26.0Patch availableGHSA-48jh-3gj7-fg8v
  • vllm Vendorvllm-project Affected before 0.26.0 Fixed in 0.26.0 Patch available CNA
  • vllm (PyPI) Vendor— Affected before 0.26.0 Fixed in 0.26.0 Patch available GHSA-48jh-3gj7-fg8v

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:vllm:vllm:*:*:*:*:*:*:*:*before 0.26.0VulnerablevLLM
  • cpe:2.3:a:vllm:vllm:*:*:*:*:*:*:*:* Versions before 0.26.0 Vulnerable ·vLLM

Remediation

  • Fix · CNA vllm (vllm-project) Fixed in 0.26.0
  • Fix · GHSA-48jh-3gj7-fg8v vllm (PyPI) Fixed in 0.26.0 Advisory →

Red Hat 26 advisories

  • RHSA-2026:94738 Released 2026-11-03 · Red Hat rating Critical
    Red Hat AI Inference 3.5.3 (CUDA)
    • Red Hat AI Inference Server 3.5 registry.redhat.io/rhaii/vllm-cuda-rhel9
  • RHSA-2026:94721 Released 2026-11-03 · Red Hat rating Critical
    Red Hat AI Inference Tech Preview 3.5.3 (Gaudi)
    • Red Hat AI Inference Server 3.5 registry.redhat.io/rhaii/vllm-gaudi-rhel9
  • RHSA-2026:94717 Released 2026-11-03 · Red Hat rating Critical
    Red Hat AI Inference 3.5.3 (Spyre)
    • Red Hat AI Inference Server 3.5 registry.redhat.io/rhaii/vllm-spyre-rhel9
Show 23 more Red Hat advisories
  • RHSA-2026:94709 Released 2026-11-03 · Red Hat rating Critical
    Red Hat AI Inference 3.5.3 (ROCm)
    • Red Hat AI Inference Server 3.5 registry.redhat.io/rhaii/vllm-rocm-rhel9
  • RHSA-2026:94702 Released 2026-11-03 · Red Hat rating Critical
    Red Hat AI Inference 3.5.3 (CPU)
    • Red Hat AI Inference Server 3.5 registry.redhat.io/rhaii/vllm-cpu-rhel9
  • RHSA-2026:92452 Released 2026-10-29 · Red Hat rating Critical
    Red Hat Enterprise Linux AI 3.5.2 enhancement update
    • Red Hat Enterprise Linux AI 3.5 registry.redhat.io/rhelai3/bootc-aws-cuda-rhel9, registry.redhat.io/rhelai3/bootc-azure-cuda-rhel9, registry.redhat.io/rhelai3/bootc-azure-rocm-rhel9 +3
  • RHSA-2026:92449 Released 2026-10-29 · Red Hat rating Critical
    Red Hat Enterprise Linux AI 3.5.2 enhancement update
    • Red Hat Enterprise Linux AI 3.5 registry.redhat.io/rhelai3/disk-image-cuda-rhel9
  • RHSA-2026:84734 Released 2026-10-19 · Red Hat rating Critical
    RHOAI 3.4.5 - Red Hat OpenShift AI
    • Red Hat OpenShift AI 3.4 registry.redhat.io/rhoai/odh-ai-gateway-payload-processing-rhel9, registry.redhat.io/rhoai/odh-automl-rhel9, registry.redhat.io/rhoai/odh-autorag-rhel9 +47
  • RHSA-2026:82415 Released 2026-10-13 · Red Hat rating Critical
    Red Hat AI Inference 3.5.2 (cpu)
    • Red Hat AI Inference Server 3.5 registry.redhat.io/rhaii/vllm-cpu-rhel9
  • RHSA-2026:82371 Released 2026-10-13 · Red Hat rating Critical
    Red Hat AI Inference 3.5.2 (spyre)
    • Red Hat AI Inference Server 3.5 registry.redhat.io/rhaii/vllm-spyre-rhel9
  • RHSA-2026:82368 Released 2026-10-13 · Red Hat rating Critical
    Red Hat AI Inference 3.5.2 (cuda)
    • Red Hat AI Inference Server 3.5 registry.redhat.io/rhaii/vllm-cuda-rhel9
  • RHSA-2026:82061 Released 2026-10-13 · Red Hat rating Critical
    Red Hat AI Inference Tech Preview 3.5.2 (Gaudi)
    • Red Hat AI Inference Server 3.5 registry.redhat.io/rhaii/vllm-gaudi-rhel9
  • RHSA-2026:82059 Released 2026-10-13 · Red Hat rating Critical
    Red Hat AI Inference 3.5.2 (ROCm)
    • Red Hat AI Inference Server 3.5 registry.redhat.io/rhaii/vllm-rocm-rhel9
  • RHSA-2026:76150 Released 2026-10-05 · Red Hat rating Important
    Red Hat Enterprise Linux AI 3.4.5 security update
    • Red Hat Enterprise Linux AI 3.4 registry.redhat.io/rhelai3/bootc-aws-cuda-rhel9, registry.redhat.io/rhelai3/bootc-azure-cuda-rhel9, registry.redhat.io/rhelai3/bootc-azure-rocm-rhel9 +3
  • RHSA-2026:76149 Released 2026-10-05 · Red Hat rating Important
    Red Hat Enterprise Linux AI 3.4.5 security update
    • Red Hat Enterprise Linux AI 3.4 registry.redhat.io/rhelai3/disk-image-cuda-rhel9
  • RHSA-2026:76043 Released 2026-10-05 · Red Hat rating Important
    Red Hat Enterprise Linux AI 3.3.7 security update
    • Red Hat Enterprise Linux AI 3.3 registry.redhat.io/rhelai3/disk-image-cuda-rhel9
  • RHSA-2026:76041 Released 2026-10-05 · Red Hat rating Important
    Red Hat Enterprise Linux AI 3.3.7 security update
    • Red Hat Enterprise Linux AI 3.3 registry.redhat.io/rhelai3/bootc-aws-cuda-rhel9, registry.redhat.io/rhelai3/bootc-azure-cuda-rhel9, registry.redhat.io/rhelai3/bootc-azure-rocm-rhel9 +3
  • RHSA-2026:70995 Released 2026-09-23 · Red Hat rating Important
    Red Hat AI Inference 3.4.5 (rocm)
    • Red Hat AI Inference Server 3.4 registry.redhat.io/rhaii/vllm-rocm-rhel9
  • RHSA-2026:70979 Released 2026-09-23 · Red Hat rating Important
    Red Hat AI Inference 3.4.5 (cuda)
    • Red Hat AI Inference Server 3.4 registry.redhat.io/rhaii/vllm-cuda-rhel9
  • RHSA-2026:70969 Released 2026-09-23 · Red Hat rating Important
    Red Hat AI Inference 3.4.5 (spyre)
    • Red Hat AI Inference Server 3.4 registry.redhat.io/rhaii/vllm-spyre-rhel9
  • RHSA-2026:70965 Released 2026-09-23 · Red Hat rating Important
    Red Hat AI Inference 3.4.5 (cpu)
    • Red Hat AI Inference Server 3.4 registry.redhat.io/rhaii/vllm-cpu-rhel9
  • RHSA-2026:69469 Released 2026-09-21 · Red Hat rating Important
    Red Hat AI Inference 3.4.5 (rocm)
    • Red Hat AI Inference Server 3.4 registry.redhat.io/rhaii/vllm-rocm-rhel9
  • RHSA-2026:69467 Released 2026-09-21 · Red Hat rating Important
    Red Hat AI Inference 3.4.5 (cuda)
    • Red Hat AI Inference Server 3.4 registry.redhat.io/rhaii/vllm-cuda-rhel9
  • RHSA-2026:69466 Released 2026-09-21 · Red Hat rating Important
    Red Hat AI Inference 3.4.5 (cpu)
    • Red Hat AI Inference Server 3.4 registry.redhat.io/rhaii/vllm-cpu-rhel9
  • RHSA-2026:69464 Released 2026-09-21 · Red Hat rating Important
    Red Hat AI Inference 3.4.5 (spyre)
    • Red Hat AI Inference Server 3.4 registry.redhat.io/rhaii/vllm-spyre-rhel9
  • RHSA-2026:68699 Released 2026-09-17 · Red Hat rating Important
    Red Hat AI Inference Server 3.3.7 (CUDA)
    • Red Hat AI Inference Server 3.3 registry.redhat.io/rhaiis/vllm-cuda-rhel9

Vendor assessments

Red Hat

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

ProductStatusPlan or fix
Red Hat AI Inference ServerAffectedNo fix yet
Red Hat Enterprise Linux AI (RHEL AI) 3AffectedNo fix planned: Will not fix
Red Hat OpenShift AI (RHOAI)AffectedNo fix yet
Red Hat AI Inference Server 3.3Fixed RHSA-2026:68699
Red Hat AI Inference Server 3.4Fixed RHSA-2026:69464, RHSA-2026:69466, RHSA-2026:69467, RHSA-2026:69469, RHSA-2026:70965, RHSA-2026:70969, RHSA-2026:70979, RHSA-2026:70995
Red Hat AI Inference Server 3.5Fixed RHSA-2026:82059, RHSA-2026:82061, RHSA-2026:82368, RHSA-2026:82371, RHSA-2026:82415, RHSA-2026:94702, RHSA-2026:94709, RHSA-2026:94717, RHSA-2026:94721, RHSA-2026:94738
Red Hat Enterprise Linux AI 3.3Fixed RHSA-2026:76041, RHSA-2026:76043
Red Hat Enterprise Linux AI 3.4Fixed RHSA-2026:76149, RHSA-2026:76150
Red Hat Enterprise Linux AI 3.5Fixed RHSA-2026:92449, RHSA-2026:92452
Red Hat OpenShift AI 3.4Fixed RHSA-2026:84734
Not affected: 3 products
  • Red Hat Enterprise Linux AI 3.3
  • Red Hat OpenShift AI (RHOAI)
  • Red Hat OpenShift AI 3.4

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-73556
  2. 2026-10-03 Alias added: GHSA-48jh-3gj7-fg8v
  3. 2026-10-06 Fix available: RHSA-2026:76149 · Red Hat
  4. 2026-10-06 Fix available: RHSA-2026:76150 · Red Hat
  5. 2026-10-06 Fix available: RHSA-2026:76043 · Red Hat
  6. 2026-10-06 Fix available: RHSA-2026:76041 · Red Hat
  7. 2026-10-06 Fix available: Red Hat Enterprise Linux AI 3.3, Red Hat Enterprise Linux AI 3.4 · Red Hat
  8. 2026-10-07 Affected versions changed · Red Hat
  9. 2026-10-09 Affected versions changed · Red Hat
  10. 2026-10-13 Fix available: RHSA-2026:82061 · Red Hat
  11. 2026-10-13 Fix available: RHSA-2026:82059 · Red Hat
  12. 2026-10-13 Fix available: Red Hat AI Inference Server 3.5 · Red Hat
  13. 2026-10-14 Fix available: RHSA-2026:82368 · Red Hat
  14. 2026-10-14 Fix available: RHSA-2026:82415 · Red Hat
  15. 2026-10-14 Fix available: RHSA-2026:82371 · Red Hat
  16. 2026-10-15 Affected versions changed · Red Hat
  17. 2026-10-20 Fix available: RHSA-2026:84734 · Red Hat
  18. 2026-10-20 Fix available: Red Hat OpenShift AI 3.4 · Red Hat
  19. 2026-10-30 Fix available: RHSA-2026:92452 · Red Hat
  20. 2026-10-30 Fix available: RHSA-2026:92449 · Red Hat
  21. 2026-10-30 Fix available: Red Hat Enterprise Linux AI 3.5 · Red Hat
  22. 2026-11-04 Fix available: RHSA-2026:94717 · Red Hat
  23. 2026-11-04 Fix available: RHSA-2026:94709 · Red Hat
  24. 2026-11-04 Fix available: RHSA-2026:94738 · Red Hat
  25. 2026-11-04 Fix available: RHSA-2026:94702 · Red Hat
  26. 2026-11-04 Fix available: RHSA-2026:94721 · Red Hat
  27. 2026-11-04 Affected versions changed · Red Hat

References

Patch 2

Advisory 2

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