CVE-2026-93838

SGLang through 0.5.20 Unbounded Memory Allocation via STAGING_REQ chunk_idx

Published Sep 18, 2026 CVSS 4.0 · 8.2 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Sgl-project
Sgl-project sglang
Vendors & Products Sgl-project
Sgl-project sglang
Type Values Removed Values Added
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.
Title SGLang through 0.5.20 Unbounded Memory Allocation via STAGING_REQ chunk_idx
First Time appeared Lmsys
Lmsys sglang
Weaknesses CWE-770
CPEs cpe:2.3:a:lmsys:sglang:*:*:*:*:*:*:*:*
Vendors & Products Lmsys
Lmsys sglang
References
Metrics cvssV3_1

{'score': 5.9, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H'}

cvssV4_0

{'score': 8.2, 'vector': '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'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
VulnCheck
Published
Updated
Sep 24, 2026, 2:23 PM
Reserved
Sep 18, 2026, 6:16 PM
Status
Deferred
Published
Sep 18, 2026, 8:17 PM
Modified
Sep 22, 2026, 8:43 PM