LMCache up to 0.5.4 KV Cache utils.py hex_hash_to_int16 weak hash

Summaryinfo

A vulnerability was found in LMCache up to 0.5.4. It has been classified as problematic. This vulnerability affects the function hex_hash_to_int16 of the file lmcache/integration/vllm/utils.py of the component KV Cache Handler. The manipulation leads to weak hash. This vulnerability is documented as CVE-2026-10813. The attack needs to be performed locally. Additionally, an exploit exists. Upgrading the affected component is recommended. 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."

Detailsinfo

A vulnerability was found in LMCache up to 0.5.4. It has been rated as problematic. This issue affects the function hex_hash_to_int16 of the file lmcache/integration/vllm/utils.py of the component KV Cache Handler. The manipulation with an unknown input leads to a weak hash vulnerability. Using CWE to declare the problem leads to CWE-328. The product uses an algorithm that produces a digest (output value) that does not meet security expectations for a hash function that allows an adversary to reasonably determine the original input (preimage attack), find another input that can produce the same hash (2nd preimage attack), or find multiple inputs that evaluate to the same hash (birthday attack). Impacted is integrity, and availability.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-10813. The exploitation is known to be difficult. An attack has to be approached locally. Technical details as well as a public exploit are known. MITRE ATT&CK project uses the attack technique T1600.001 for this issue.

The exploit is available at github.com. It is declared as proof-of-concept. 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."

Upgrading to version 0.5.5 eliminates this vulnerability. The upgrade is hosted for download at pypi.org. Applying the patch ce08eea76ce5898200efee55f4932fd07a7cabeb is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-34290). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Name

• LMCache

Version

• 0.5.0
• 0.5.1
• 0.5.2
• 0.5.3
• 0.5.4

License

• open-source

Website

• Product: https://github.com/LMCache/LMCache/

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Submitinfo

Accepted

• Submit #831641: LMCache 729ff73 Cache poisoning (by Dem00)

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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