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.
Published: 2026-09-29
Score: 8.7 High
EPSS: < 1% Very Low
KEV: No
Impact: Denial of Service (scheduler crash or request hang)
Action: Apply Patch
AI Analysis

Impact

A missing duplicate bootstrap_room validation allows an attacker to send concurrent /generate requests with identical bootstrap_room values through the Mooncake KV transfer backend. When these requests are processed, the scheduler may crash or other users’ requests are held until the transfer times out, resulting in a loss of availability.

Affected Systems

The effect occurs in the sgl-project SGLang product, versions up to and including 0.5.20, when operating in prefill/decode disaggregation mode. The vulnerability is specific to the Mooncake KV transfer backend used by SGLang.

Risk and Exploitability

The CVSS score of 8.7 indicates a high severity. The EPSS score is not available, and the vulnerability is not listed in CISA’s KEV catalog. Attackers can exploit the flaw from any network location that can reach the /generate endpoint, and the attack does not require authentication. The impact is purely availability, with potential to affect all users of the impacted instance.

Generated by OpenCVE AI on September 30, 2026 at 00:51 UTC.

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

  • Upgrade SGLang to a release newer than 0.5.20 that includes the duplicate bootstrap_room validation fix.
  • ict access to the /generate endpoint by requiring authentication or applying rate limiting to mitigate unauthenticated or high‑volume requests.
  • Implement application‑level checks to reject concurrent requests that contain duplicate bootstrap_room values as an interim workaround.

Generated by OpenCVE AI on September 30, 2026 at 00:51 UTC.

Tracking

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Advisories

No advisories yet.

History

Tue, 29 Sep 2026 18:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Tue, 29 Sep 2026 16:30:00 +0000

Type Values Removed Values Added
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.
Title SGLang through 0.5.20 Denial of Service via Duplicate bootstrap_room
First Time appeared Lmsys
Lmsys sglang
Weaknesses CWE-694
CPEs cpe:2.3:a:lmsys:sglang:*:*:*:*:*:*:*:*
Vendors & Products Lmsys
Lmsys sglang
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

cvssV4_0

{'score': 8.7, 'vector': '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'}

Subscriptions

Lmsys Sglang
cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-09-29T17:33:09.537Z

Reserved: 2026-09-29T15:50:38.222Z

Link: CVE-2026-102634

cve-icon Vulnrichment

Updated: 2026-09-29T17:32:41.870Z

cve-icon NVD

Status : Deferred

Published: 2026-09-29T17:17:07.147

Modified: 2026-09-29T18:17:09.033

Link: CVE-2026-102634

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-30T01:00:09Z

Weaknesses
  • CWE-694

    Use of Multiple Resources with Duplicate Identifier