# CVE-2026-93838: SGLang through 0.5.20 Unbounded Memory Allocation via STAGING_REQ chunk_idx

> Attackers with internal ZMQ access can cause denial of service in SGLang by sending large chunk indices, exhausting memory in disaggregated deployments.

- **Severity:** High 8.2 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 18 Sep 2026
- **Updated:** 24 Sep 2026
- **Also known as:** GHSA-2wcg-j54r-m6wm

## What is CVE-2026-93838?

CVE-2026-93838 is a high-severity denial of service vulnerability in sgl-project sglang, published on 18 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

SGLang versions through 0.5.20 contain an unbounded memory allocation vulnerability in handle_staging_req() that fails to validate chunk_idx from ZMQ STAGING_REQ frames in prefill/decode disaggregation deployments. Attackers with access to the decode engine's internal ZMQ rank port can send a frame with an extremely large chunk_idx value, causing the scheduler to allocate memory until the system runs out and terminates the process.

Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling)

## Which versions are affected by CVE-2026-93838?


## How do I fix CVE-2026-93838?

Upgrade to a fixed version.

## Is CVE-2026-93838 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-93838 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-93838 and fix it if it is affected.

What it is: CVE-2026-93838 is a high-severity denial of service vulnerability in sgl-project sglang, published on 18 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-93838 exists.

Affected product: sgl-project sglang. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-93838/ (Markdown: https://insights.sbomify.com/CVE-2026-93838/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-93838
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-93838
- OSV: https://osv.dev/vulnerability/CVE-2026-93838

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-93838/
Summaries are generated and may contain mistakes; the official description above is the record.