SGLang through 0.5.20 Unbounded Memory Allocation via STAGING_REQ chunk_idx
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- Present
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- No fix listed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-770.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| sgl-project | sglang | up to 0.5.20 | — | No fix listed | CNA |
- sglang Vendorsgl-project Affected up to 0.5.20 Fixed in — No fix listed CNA
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2026-93838
- 2026-10-03 Alias added: GHSA-2wcg-j54r-m6wm
- 2026-10-14 EPSS moved to the 50th–90th percentile
References
Other 5
- GitHub Issue #39764
- https://github.com/sgl-project/sglang
- https://github.com/sgl-project/sglang/blob/v0.5.20/python/sglang/srt/disaggregation/common/staging_handler.py#L781
- https://github.com/sgl-project/sglang/blob/v0.5.20/python/sglang/srt/disaggregation/common/staging_handler.py#L848-L860
- https://github.com/sgl-project/sglang/blob/v0.5.20/python/sglang/srt/disaggregation/common/conn.py#L1636-L1640
More sgl-project vulnerabilities
- TI-2026-76247 Denial of service in SGLang expert-distribution recording endpoint CVSS 4.0HIGH 8.7
- TI-2026-70996 SGLang disables decompression bomb check, enabling denial of service CVSS 4.0HIGH 8.7
- TI-2026-70994 SGLang Memory Exhaustion DoS via Qwen-VL Video Preprocessing CVSS 4.0HIGH 8.7
- TI-2026-70993 Decompression amplification in SGLang load_audio exhausts memory CVSS 4.0HIGH 8.7
- TI-2026-65453 SGLang through 0.5.20 Denial of Service via Duplicate bootstrap_room CVSS 4.0HIGH 8.7
- TI-2026-75290 Code injection in SGLang debug dumper filter CVSS 4.0CRITICAL 9.2
Sources
- CVE-2026-93838 · CVE Program
- CVE-2026-93838 · NVD
- FIRST EPSS
- GHSA-2wcg-j54r-m6wm · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences