CVE-2026-93838CWE-770denial-of-service

CVE-2026-93838

Medium · published September 19, 2026

CVSS v3.1
5.9
EPSS
1%
Percentile
50.6
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
5.9 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v4.0
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
EPSS
0.00652 · 50.6th percentile
Weakness
CWE-770 · Allocation of Resources Without Limits or Throttling
Published
2026-09-19T00:17Z
References (7)
https://github.com/sgl-project/sglang · [email protected]https://github.com/sgl-project/sglang/blob/v0.5.20/python/sglang/srt/disaggregation/common/conn.py#L1636-L1640 · [email protected]https://github.com/sgl-project/sglang/blob/v0.5.20/python/sglang/srt/disaggregation/common/staging_handler.py#L781 · [email protected]https://github.com/sgl-project/sglang/blob/v0.5.20/python/sglang/srt/disaggregation/common/staging_handler.py#L848-L860 · [email protected]https://github.com/sgl-project/sglang/issues/39764 · [email protected]https://www.vulncheck.com/advisories/sglang-through-0.5.20-unbounded-memory-allocation-via-staging-req-chunk-idx · [email protected]https://github.com/sgl-project/sglang/issues/39764 · 134c704f-9b21-4f2e-91b3-4a467353bcc0
EPSS history
Timeline
  • 20 SEP 03:25Z
    EPSS moved — → 0%
    epss
  • 18 SEP 19:06Z
    SGLang through 0.5.20 Unbounded Memory Allocation via STAGING_REQ chunk_idx
    cvelistv5