Bug 2560429 (CVE-2026-116180)

Summary: CVE-2026-116180 vllm: vLLM: Denial of Service via uninitialized log probability tensors
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: alinfoot, bbrownin, dtrifiro, mwoodson, weaton
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in vLLM. A remote client sharing the inference engine can trigger a Denial of Service (DoS) by submitting requests with prompt log probabilities enabled against a cached prefix. Because uninitialized memory is allocated for log probability tensors, cached token positions remain unpopulated, causing the tokenizer to encounter invalid values during decoding. This causes an overflow error that crashes the core engine process and terminates all concurrent tenant requests.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-10-25 13:34:06 UTC 
vLLM from 0.8.5 before 0.31.0 has a denial of service flaw. LogprobsTensors.empty_cpu() in vllm/v1/outputs.py allocates an uninitialized int32 tensor, and the V1 model runner leaves prompt positions reported as computed by a KV connector unwritten. A client sharing the engine can send prompt_logprobs (or echo with logprobs) against a connector-cached prefix, making tokenizer decode raise OverflowError, which crashes EngineCore and drops all co-tenant requests.