Bug 2538411 (CVE-2026-93989)

Summary: CVE-2026-93989 vllm: vLLM: Cross-request logits corruption via out-of-bounds token indices
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: low Docs Contact:
Priority: low    
Version: unspecifiedCC: alinfoot, bbrownin, dtrifiro, 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 attacker can exploit a vulnerability by providing malformed input related to 'bad words' token processing. This can lead to out-of-bounds memory access, corrupting the internal data (logits memory) used for generating responses for other concurrent requests. As a result, different in-flight requests may receive incorrect or unintended tokens, impacting the integrity of the generated output.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Description OSIDB Bzimport 2026-09-22 18:29:28 UTC 
vLLM through 0.29.0 fails to properly validate bad_words token indices against the model's generation output width in SamplingParams.update_from_tokenizer(). Attackers can supply out-of-bounds token indices that corrupt logits memory of concurrent requests, causing different in-flight HTTP requests to return incorrect tokens.