High

vllm API endpoints vulnerable to Denial of Service Attacks

  • Disclosed: 21.08.2025
  • Updated: 11.10.2026 15:17

Summary

A Denial of Service (DoS) vulnerability can be triggered by sending a single HTTP GET request with an extremely large header to an HTTP endpoint. This results in server memory exhaustion, potentially leading to a crash or unresponsiveness. The attack does not require authentication, making it exploitable by any remote user.

Details

The vulnerability leverages the abuse of HTTP headers. By setting a header such as X-Forwarded-For to a very large value like ("A" * 5_800_000_000), the server's HTTP parser or application logic may attempt to load the entire request into memory, overwhelming system resources.

Impact

What kind of vulnerability is it? Who is impacted? Type of vulnerability: Denial of Service (DoS)

Resolution

Upgrade to a version of vLLM that includes appropriate HTTP limits by deafult, or use a proxy in front of vLLM which provides protection against this issue.

Affected software

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PlatformPackageVulnerable versionsFixed in
Python (PyPI) vllm >= 0.1.0, < 0.10.1.1 0.10.1.1

References

CVSS score 7.5/10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE)
CWE-400
Platform
Python (PyPI)
Package
vllm
Disclosed
21.08.2025
Updated
11.10.2026 15:17

Sources and licenses

OSV / GitHub Advisory Database - PYSEC-2026-2021 - PyPA Advisory Database; CC BY 4.0

OSV / GitHub Advisory Database - GHSA-rxc4-3w6r-4v47 - CC BY 4.0

Vulnerability history: vllm

All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.

All (94) in the archive
Total entries
94
First → latest
09.2024 10.2026
Without a fix
5
Exploited in attacks
0

Severity breakdown

  • Critical 9
  • High 23
  • Medium 47
  • Low 4
  • Unrated 11

Disclosures per year

  1. 2024: 2
  2. 2025: 30
  3. 2026: 62
Severity:
  1. High · 7.5 CVE-2026-54234 >= 0.17.1, < 0.24.0 0.24.0
  2. High CVE-2026-55514 >= 0.12.0, < 0.24.0 0.24.0
  3. Critical · 9.1 CVE-2026-48746 >= 0.3.0, < 0.22.0 0.22.0
  4. Critical · 9.8 CVE-2026-22778 >= 0.8.3, < 0.14.1 0.14.1
  5. High · 8.8 CVE-2026-22807 >= 0.10.1, < 0.14.0 0.14.0
  6. High · 8.8 CVE-2026-56340 >= 0.10.2, < 0.13.0 0.13.0
  7. High · 6.5 CVE-2025-62372 >= 0.5.5, < 0.11.1 0.11.1
  8. High · 8.8 CVE-2025-62164 >= 0.10.2, < 0.11.1 0.11.1
  9. High · 7.5 CVE-2025-59425 < 0.11.0 0.11.0
  10. High · 8.8 CVE-2025-9141 >= 0.10.0, < 0.10.1.1 0.10.1.1
  11. vllm API endpoints vulnerable to Denial of Service Attacks this entry
    High · 7.5 CVE-2025-48956 >= 0.1.0, < 0.10.1.1 0.10.1.1
  12. Critical · 9.8 CVE-2025-47277 >= 0.6.5, < 0.8.5 0.8.5
  13. High · 8.0 CVE-2025-30165 >= 0.5.2, < 0.10.0 0.10.0
  14. Critical · 10.0 CVE-2025-32444 >= 0.6.5, < 0.8.5 0.8.5
  15. High · 7.5 CVE-2025-30202 >= 0.5.2, < 0.8.5 0.8.5
  16. Critical · 9.8 CVE-2024-11041 <= 0.6.2 no fix
  17. Critical · 9.0 CVE-2025-29783 >= 0.6.5, < 0.8.0 0.8.0
  18. High · 7.5 CVE-2024-8768 < 0.5.5 0.5.5

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