vLLM using built-in hash() from Python 3.12 leads to predictable hash collisions in vLLM prefix cache
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
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| vllm-project | vllm | affected |
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No data available yet.
| Source | ID | Title |
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EUVD |
EUVD-2025-4074 | vLLM is a high-throughput and memory-efficient inference and serving engine for LLMs. Maliciously constructed statements can lead to hash collisions, resulting in cache reuse, which can interfere with subsequent responses and cause unintended behavior. Prefix caching makes use of Python's built-in hash() function. As of Python 3.12, the behavior of hash(None) has changed to be a predictable constant value. This makes it more feasible that someone could try exploit hash collisions. The impact of a collision would be using cache that was generated using different content. Given knowledge of prompts in use and predictable hashing behavior, someone could intentionally populate the cache using a prompt known to collide with another prompt in use. This issue has been addressed in version 0.7.2 and all users are advised to upgrade. There are no known workarounds for this vulnerability. |
Github GHSA |
GHSA-rm76-4mrf-v9r8 | vLLM uses Python 3.12 built-in hash() which leads to predictable hash collisions in prefix cache |
No CVSS v4.0
No CVSS v3.0
No CVSS v2
This CVE is not in the KEV list.
Exploit prediction score: < 1% (0.191% probability within 30 days)
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| First Time appeared |
Vllm
Vllm vllm |
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| CPEs | cpe:2.3:a:vllm:vllm:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Vllm
Vllm vllm |
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| Metrics |
ssvc
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| Weaknesses | CWE-916 | |
| References |
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| Metrics |
threat_severity
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threat_severity
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| Description | vLLM is a high-throughput and memory-efficient inference and serving engine for LLMs. Maliciously constructed statements can lead to hash collisions, resulting in cache reuse, which can interfere with subsequent responses and cause unintended behavior. Prefix caching makes use of Python's built-in hash() function. As of Python 3.12, the behavior of hash(None) has changed to be a predictable constant value. This makes it more feasible that someone could try exploit hash collisions. The impact of a collision would be using cache that was generated using different content. Given knowledge of prompts in use and predictable hashing behavior, someone could intentionally populate the cache using a prompt known to collide with another prompt in use. This issue has been addressed in version 0.7.2 and all users are advised to upgrade. There are no known workarounds for this vulnerability. | |
| Title | vLLM using built-in hash() from Python 3.12 leads to predictable hash collisions in vLLM prefix cache | |
| Weaknesses | CWE-354 | |
| References |
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| Metrics |
cvssV3_1
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