Low

LMCache: 16-bit multimodal hash collision can poison KV cache entries

  • Disclosed: 04.06.2026
  • Updated: 11.10.2026 14:18

A flaw has been found in LMCache up to 0.4.6. This affects the function hex_hash_to_int16 of the file lmcache/integration/vllm/utils.py of the component KV Cache Handler. Executing a manipulation can lead to use of weak hash. The attack needs to be launched locally. The attack requires a high level of complexity. It is indicated that the exploitability is difficult. The exploit has been published and may be used. The pull request to fix this issue awaits acceptance.

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Python (PyPI) lmcache <= 0.4.6 no fix

References

CVSS score 3.6/10
CVSS vector
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:L
Weakness (CWE)
CWE-327
Platform
Python (PyPI)
Package
lmcache
Disclosed
04.06.2026
Updated
11.10.2026 14:18

Sources and licenses

OSV / GitHub Advisory Database - PYSEC-2026-3480 - PyPA Advisory Database; CC BY 4.0

OSV / GitHub Advisory Database - GHSA-3hh9-752g-5g22 - CC BY 4.0

Vulnerability history: lmcache

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

This is the only known vulnerability of this package.

Know which vulnerabilities affect your application

With the DockRay integration and software inventory enabled, DockRay checks reported component versions against known vulnerabilities and notifies you about confirmed matches. Coverage depends on the supported technology and available advisory data.

Connect your application
DockRay newsletter

Application security in your inbox

Important vulnerabilities, actionable guidance and practical advice for your applications. Choose your technologies and follow what matters to your project.

  • A daily digest of new vulnerabilities, critical ones included.
  • Notifications about important updates.
  • Practical advice on application security and monitoring.

Leave empty to receive updates for every technology.

Free to subscribe. Unsubscribe with one click in any email.