Buffer overflow in Vllm
CVE-2026-56340
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.
Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.006 (48.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 49th percentile — 48.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000
Affected products
- Vllm — versions 0.10.2, 0.13.0
Weakness classification (CWE)
References
- GHSA Advisory GHSA-mcmc-2m55-j8jj (vendor-advisory, Vendor Advisory)
- VulnCheck Advisory: vLLM - Denial of Service via Unvalidated Multimodal Embeddings (Third Party Advisory, third-party-advisory)
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Frequently asked questions
- What is CVE-2026-56340?
- CVE-2026-56340 is a high-severity vulnerability in Vllm, classified under Improper Input Validation. CVSS score: 8.8/10. Published 2026-06-20.
- How severe is CVE-2026-56340?
- High severity. CVSS v3 base score is 8.8 out of 10.