Vulnerability · Published Sep 18, 2026 · Assigned by VulnCheck

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

Medium 5.9

In plain English

A medium-severity resource allocation without limits in sglang from sgl-project. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 51% of all known vulnerabilities).

Severity (CVSS 3.1)5.9Medium

Exploit odds (30 days)0.7%top 48.6% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

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.

Affected products (as reported)

Vendor	Product	Versions
sgl-project	sglang	0 – through 0.5.20

Weakness: CWE-770 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

References

GitHub Issue #39764 issue-tracking
https://github.com/sgl-project/sglang product
https://github.com/sgl-project/sglang/blob/v0.5.20/python/sglang/srt/disaggregation/common/staging_handler.py#L781 technical-description
https://github.com/sgl-project/sglang/blob/v0.5.20/python/sglang/srt/disaggregation/common/staging_handler.py#L848-L860 technical-description
https://github.com/sgl-project/sglang/blob/v0.5.20/python/sglang/srt/disaggregation/common/conn.py#L1636-L1640 technical-description
VulnCheck Advisory: SGLang through 0.5.20 Unbounded Memory Allocation via STAGING_REQ chunk_idx third-party-advisory