High severity · published Jun 20, 2026
CVE-2026-56340
vLLM - Denial of Service via Unvalidated Multimodal Embeddings
7.5
CVSS
0.6%
EPSS
No
On KEV
Description
vLLM versions >= 0.10.2 and < 0.13.0 are missing sparse tensor validation in multimodal embeddings processing. Because PyTorch disables sparse tensor invariant checks by default, an attacker can submit crafted embedding requests with malformed (negative or out-of-bounds) tensor indices, when the prompt-embeds feature is enabled, to trigger crashes or resource exhaustion (denial of service), with potential for out-of-bounds/write-what-where memory corruption. This continues CVE-2025-62164, whose prior fix only disabled the feature by default rather than addressing the root cause.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.6% · higher than 51% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
VL
vLLM · vLLM
0.10.2 before 0.13.0 · source: vendor, NVD
RH
Red Hat AI Inference Server · Red Hat
All versions, or not specified · source: CISA
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-56340
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-56340
Vendor Advisory
https://github.com/vllm-project/vllm/security/advisories/GHSA-mcmc-2m55-j8jj
Third Party Advisory
https://www.vulncheck.com/advisories/vllm-denial-of-service-via-unvalidated-multimodal-embeddings
access.redhat.com
https://access.redhat.com/security/cve/CVE-2026-56340
bugzilla.redhat.com
https://bugzilla.redhat.com/show_bug.cgi?id=2491060
security.access.redhat.com
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-56340.json
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