# CVE-2026-102634: SGLang through 0.5.20 Denial of Service via Duplicate bootstrap_room

> Unauthenticated attackers can crash scheduler processes or hang requests in SGLang by sending duplicate bootstrap_room values in prefill/decode disaggregation mode.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/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:** 29 Sep 2026
- **Updated:** 29 Sep 2026
- **Also known as:** GHSA-mjgp-hgfr-77jq, openSUSE-SU-2026:11947-1

## What is CVE-2026-102634?

CVE-2026-102634 is a high-severity denial of service vulnerability in sgl-project sglang, published on 29 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

SGLang through 0.5.20 in prefill/decode disaggregation mode fails to validate duplicate bootstrap_room fields in /generate requests with Mooncake KV transfer backend. Unauthenticated attackers can send concurrent requests with identical bootstrap_room values to crash scheduler processes or hang other users' requests until transfer timeout.

Weakness: CWE-694 (Use of Multiple Resources with Duplicate Identifier)

## Which versions are affected by CVE-2026-102634?


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `python-sglang` | openSUSE:Tumbleweed | All versions | 0.5.20-2.1 |

## How do I fix CVE-2026-102634?

Apply the vendor's patch.

## Is CVE-2026-102634 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-102634 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-102634 and fix it if it is affected.

What it is: CVE-2026-102634 is a high-severity denial of service vulnerability in sgl-project sglang, published on 29 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-2026-102634 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-2026-102634/ (Markdown: https://insights.sbomify.com/CVE-2026-102634/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-102634
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-102634
- OSV: https://osv.dev/vulnerability/CVE-2026-102634

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-102634/
Summaries are generated and may contain mistakes; the official description above is the record.