Security Digest · Vulnerability record
CVE-2026-105192: LMCache: Remote code execution via unsafe deserialization in multiprocess mode transport
LMCache multiprocess mode, also called distributed mode, opens an unauthenticated ZeroMQ ROUTER so worker processes can register and share KV cache blocks.
CVSS 9.8 Critical EPSS 0.5% · p41
Should you act?
Critical and remotely reachable
No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.5%, percentile 41: FIRST’s model estimates a 0.5% chance of exploitation activity in the next 30 days, higher than 41% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes
lmcache(PyPI) >= 0.3.9, < 0.5.6, fixed in 0.5.6. Check your lockfile, including transitive dependencies.
What it is
LMCache multiprocess mode, also called distributed mode, opens an unauthenticated ZeroMQ ROUTER so worker processes can register and share KV cache blocks. Messages on that socket are msgpack. Extension code 1 is passed to DeviceIPCWrapper.Deserialize, which calls pickle.loads, while the server is still decoding request arguments and before the handler runs. A single unauthenticated ZMQ DEALER message to the transport port (default 5555) therefore executes code as the user the LMCache process runs as. Official container images run that process as root. The transport binds to localhost unless the operator sets a routable address with --host, which is how multi-node deployments let peers connect.
From the GitHub advisory
Summary
LMCache is vulnerable to Unauthenticated Remote Code Execution via Pickle Deserialization on the Multiprocess ZMQ Transport
Details
LMCache multiprocess mode, also called distributed mode, opens an unauthenticated ZeroMQ ROUTER so worker processes can register and share KV cache blocks. The intended clients are sibling LMCache processes. There is no CURVE, ZAP, password, or message authentication on that socket. LMCache used only inside a vLLM process does not open this port. The transport binds to localhost unless the operator sets a routable address with --host, which is how multi-node deployments let peers connect. The 9.8 score is for that routable configuration. A stock single-host install that leaves the default bind is not reachable from other machines.
Messages on the socket are msgpack. Extension code 1 is registered for DeviceIPCWrapper and is passed to DeviceIPCWrapper.Deserialize in lmcache/v1/platform/base/ipcwrapper.py, which calls pickle.loads. That hook runs from exthook in lmcache/v1/multiprocess/customtypes.py while the server is still decoding REGISTERKVCACHE arguments, before the handler runs. A single unauthenticated ZMQ DEALER message to the transport port (default 5555) therefore executes code as the user the LMCache process runs as. Official container images run that process as root.
Weakness type: CWE-502, CWE-306.
Product: lmcache (PyPI) · Assigned by: JFROG · Published: 2026-10-07
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| PyPI | lmcache | >= 0.3.9, < 0.5.6 | 0.5.6 |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| LMCache | LMCache | 0.3.9 <= * |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| JFROG | 3.1 | 9.8 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| GitHub | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: none (no login)
- User interaction: none
- Scope: unchanged
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none, automatable yes, technical impact total.
- FIRST EPSS (model of 2026-10-21): 0.48% probability of exploitation activity in the next 30 days; percentile 41.
Timeline
- — CVE record last updated
- — CVE record published by JFROG
- — GitHub-reviewed advisory GHSA-w5f2-9q9c-ff4h published (critical)
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- GitHub Advisory GHSA-w5f2-9q9c-ff4h github.com
- CVE.org record CVE-2026-105192 cve.org
- NVD entry CVE-2026-105192 nvd.nist.gov
Other references from the CVE record and advisory
- LMCache repository github.com
- lmcache on PyPI pypi.org
- DeviceIPCWrapper.Deserialize calls pickle.loads (v0.5.5) github.com
- msgpack extension code 1 decoded with pickle (v0.3.9) github.com
- github.com github.com
- github.com github.com
- github.com github.com
- github.com github.com
- github.com github.com
- github.com github.com
- github.com github.com
- blog.lmcache.ai blog.lmcache.ai
- research.jfrog.com research.jfrog.com