---
id: "CVE-2026-112270"
kind: "vulnerability"
aliases: ["CVE-2026-112270"]
title: "SGLang: unauthenticated staging messages let attackers exhaust prefill memory"
severity: "high"
cvss: 7.1
epss: null
exploited: false
status: "open"
category: "ai-tooling"
products: []
ecosystems: []
tags: ["ai-tooling", "llm-serving", "mooncake", "python", "self-hosted", "sglang"]
not_affected_if: ["isolated-network", "no-mooncake-backend"]
published_at: "2026-10-19T14:17:04+00:00"
first_seen_at: "2026-10-23T21:57:18+00:00"
updated_at: "2026-10-25T03:35:00+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-112270", "first_seen_at": "2026-10-23T21:57:18+00:00"}]
---

# SGLang: unauthenticated staging messages let attackers exhaust prefill memory

SGLang through 0.5.22, when using the Mooncake disaggregation backend, fails to limit memory allocation in handle_staging_rsp(). An unauthenticated attacker on the network can send crafted STAGING_RSP messages with huge chunk_idx values, forcing the scheduler to allocate memory until it is OOM-killed.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check whether the SGLang version is `0.5.22` or earlier, for example with `pip show sglang`.
- Check whether the server runs prefill/decode disaggregation with the Mooncake backend enabled in its launch flags or config.
- Check whether the `/route` endpoint and the prefill rank port are reachable from untrusted networks.

## Fix

- Upgrade SGLang to a version later than `0.5.22`; the sources do not name the fixed version, so check the NVD entry or the SGLang release notes.
- Until patched, restrict network access to the prefill ranks and the `/route` endpoint to trusted hosts only.
- Or disable the Mooncake disaggregation backend if it is not needed.

## Timeline

- 2026-10-23T21:57:18+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-112270

## From the sources

SGLang through 0.5.22 with the Mooncake disaggregation backend contains an uncontrolled memory allocation vulnerability in handle_staging_rsp() that lets unauthenticated network-adjacent attackers exhaust Prefill memory. Attackers can obtain the rank address from the /route endpoint and send STAGING_RSP messages with huge chunk_idx values under fresh room IDs, causing the scheduler to be OOM-killed.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_