CVE-2026-73557: vllm-project vllm Race Condition

Vulnerability summary

CVE-2026-73557 is a medium (CVSS 6.3) Race Condition vulnerability in vllm-project vllm. EPSS estimates a 0.25% chance of exploitation in the next 30 days, higher than 15.1% of scored vulnerabilities.

Timeline

1. 13-08-2026
   PublishedVulnerability first disclosed.
2. 13-08-2026
   Last modifiedVulnerability information updated.

Description

vLLM is an inference and serving engine for large language models. From 0.20.2rc0 until 0.26.0, safe_load_prompt_embeds in vllm/renderers/embed_utils.py uses torch.sparse.check_sparse_tensor_invariants, whose process-global save, enable, and restore state can be raced by concurrent prompt_embeds parts submitted to POST /v1/chat/completions through AsyncMultiModalItemTracker.resolve_items, asyncio.gather, and the default executor, allowing an invalid sparse tensor to reach tensor.to_dense despite the CVE-2025-62164 guard when enable_prompt_embeds is enabled. This issue is fixed in version 0.26.0.

• CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.