7.5

CVE-2026-100647: vLLM before 0.29.0 CPU Exhaustion via unbounded cache_salt

Analyzed
Published 26-09-2026Last modified 28-09-2026

Vulnerability summary

CVE-2026-100647 is a high (CVSS 7.5) Improper Input Validation vulnerability in vllm-project vllm. EPSS estimates a 0.35% chance of exploitation in the next 30 days, higher than 27.2% of scored vulnerabilities.

Overall risk
30/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.5/10
010
High · v3.1 (NVD)
EPSS score
0.35%
0%100%
Low · Change unavailable
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Timeline

  1. 26-09-2026
    PublishedVulnerability first disclosed.
  2. 28-09-2026
    Last modifiedVulnerability information updated.

Description

vLLM versions before 0.29.0 contain a denial-of-service vulnerability in the cache_salt parameter accepted on OpenAI-compatible and Anthropic API endpoints, which lacks maximum length validation and is processed on the single EngineCore scheduler thread. Unauthenticated attackers can send HTTP requests with multi-hundred-megabyte salt values that trigger expensive pickle serialization and SHA-256 hashing, stalling the scheduler thread and denying service to all concurrent requests.

CVSS metrics

4 scores · 2 sources · 2 versions

EPSS trend

Probability

0.35%

Chance of exploitation in the next 30 days

Percentile

27%

Versus all other CVEs

30-day change

Change unavailable

Change unavailable

27-09-202622-10-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Vllm1 product
Vllm-project1 product

2 vendors · 2 products

References

2 links