CVE-2026-56340Network attack vector

Server crash via unvalidated sparse tensor indices

Published Jun 20, 2026 · Updated Jun 20, 2026

Improper input validation in vLLM 0.10.2 and later before 0.13.0 allows remote authenticated users to crash the server. Multimodal embedding processing decodes attacker-supplied sparse tensors without enabling PyTorch invariant checks, so negative or out-of-bounds indices reach dense conversion and can cause resource exhaustion or out-of-bounds writes. The prompt-embeds feature must be enabled; it is disabled by default, and the published advisory provides no proof of code execution.

CVSS severity8.7
High
EPSS probability0.64%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in vLLM 0.10.2 and later before 0.13.0 allows remote authenticated users to crash the server. Multimodal embedding processing decodes attacker-supplied sparse tensors without enabling PyTorch invariant checks, so negative or out-of-bounds indices reach dense conversion and can cause resource exhaustion or out-of-bounds writes. The prompt-embeds feature must be enabled; it is disabled by default, and the published advisory provides no proof of code execution.

The record

CVE
CVE-2026-56340
Published
Jun 20, 2026
Updated
Jun 20, 2026
Vendor
vLLM Project
Product
vLLM
Classifications
CWE-20, CWE-787, CWE-502, CWE-123, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 20, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 20, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0.10.2 <0.13.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

vLLM Project · vLLMversion=0.10.2 <0.13.0

Published CVSS scores

8.7VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
8.8Red HatCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
8.8vLLM ProjectCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
CWE-787Out-of-bounds Write
CWE-502Deserialization of Untrusted Data
CWE-123Write-what-where Condition
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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