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JFrog Reports Critical LMCache Flaw CVE-2026-105192, a CVSS 9.8 Pickle Deserialization Bug in Multiprocess Mode, With No Fixed Version as of October 7

JFrog's October 7 advisory rates LMCache's CVE-2026-105192 at CVSS 9.8 and lists no fixed release; a fix pull request opened October 11 was still open that day.

Cybersecurity Vulnerabilities
lmcache cve-2026-105192 vulnerability deserialization llm-inference jfrog
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Overview

JFrog Security Research published an advisory on October 7, 2026 for CVE-2026-105192, a critical remote code execution flaw in LMCache, which The Hacker News describes as open-source software that speeds up large language model (LLM) servers such as vLLM. According to JFrog, the advisory lists a CVSS score of 9.8 and a JFrog severity of critical, and states that no fixed version had been published as of October 7. A pull request that would remove the vulnerable deserialization step was opened publicly on October 11 and was still open when checked that day.

What the Advisory Says

  • Identifier and score: JFrog lists CVE-2026-105192 with “CVSS 9.8” and a JFrog severity of critical. The page does not label a CVSS version or give a vector string.
  • Reporter and dates: The advisory credits Yuval Moravchick of the JFrog Security Research Team. It shows a published date of October 7, 2026 and a last-updated date of the same day.
  • Affected software: The flaw sits in LMCache’s multiprocess mode, also called distributed mode. JFrog says this mode opens an unauthenticated ZeroMQ socket so worker processes can register and share cached data, and that there is no authentication of any kind on that socket.
  • Affected versions: JFrog says the vulnerable decoding path shipped in v0.3.9 and is still present in v0.5.5, the latest PyPI release at the time, in the v0.5.6 release candidates through v0.5.6rc3, and on the development branch as of October 7, 2026. The Hacker News gives the same range, from 0.3.9 through 0.5.5 plus the release candidates and development branch.
  • Fixed versions: JFrog states “No fixed release is available as of 2026-10-07.”
  • Mechanism, at a high level: According to JFrog, a message handled while the server is still decoding its arguments reaches a call to Python’s pickle deserializer before the handler runs, so a single unauthenticated message can execute code as the user running LMCache. JFrog says the project’s official container images run that process as root.

Exposure Depends on One Setting

Both sources stress a condition. JFrog says the transport binds to localhost unless an operator sets a routable address, which is how multi-node deployments let peers connect, and that the 9.8 score applies to that routable configuration. A stock single-host install that keeps the default bind is not reachable from other machines, and LMCache used only inside a vLLM process does not open the port, per JFrog.

The Hacker News adds that LMCache’s own example Kubernetes deployment starts the server listening on every network interface. It also reports that LMCache had not published a security advisory for the flaw and that JFrog’s advisory gives operators no way to tell whether a server has already been attacked.

Mitigation Guidance and Proposed Fix

Until a release includes a fix, JFrog advises operators not to set a routable address for the multiprocess server and to keep its port on localhost or a trusted cluster network. JFrog adds that a firewall reduces who can reach the port, but any host that can still open a connection can run code as the LMCache user. For a longer-term fix, JFrog recommends replacing the serializer with a safe format and authenticating the transport.

On October 11, a contributor, maobaolong, opened pull request 5644 against LMCache’s dev branch, titled “[Security][MP] Remove pickle from device IPC descriptors (CVE-2026-105192)”. The pull request description says it replaces device-wrapper pickle with versioned, typed MessagePack descriptors validated against a fixed local allowlist. It states that workers and multiprocess servers must be upgraded together and that legacy pickle descriptors are rejected. The same description says other pickle handling and RPC authentication are “deliberately out of scope” and that the change “does not make an MP endpoint safe for arbitrary untrusted clients.” The pull request’s state was open, with no merge recorded, when checked on October 11, 2026; whether it will be merged or released was not stated.

The Hacker News reports that a GitHub user opened six additional LMCache security reports on October 6, the day before the CVE was made public. According to that outlet, the reports come from one account, rest on proof-of-concept claims, and have no CVE, no maintainer confirmation and no fix. The same article notes that the pattern of passing data from an unauthenticated network socket to pickle matches flaws researchers found in other AI inference frameworks in November 2025 and called ShadowMQ, while saying that whether LMCache’s code shares a common source with those projects has not been established.

Several points remain unknown from the sources reviewed. Neither source reports exploitation in the wild. The advisory shows no CVSS version or vector, and there is no stated date for a patched release. The status claims here reflect JFrog’s page and The Hacker News as of October 7, and the pull request as observed on October 11, 2026; later changes are not captured.