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.
CVE-2026-93838
MEDIUMPre-NVD 5.95.9
EchelonGraph scoreLOW confidence
This medium-severity CVE scores 5.9 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
Triggered by: NVD CVSS baseline
Sources: secondary
5.9EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: —CVSS: 5.9Exploit: None knownExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 5.9
- EG Score
- 5.9(low)
- EG Risk
- 31(Track)EG Risk 31/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity59% × 45%Exploitation0% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- —
- EPSS %ILE
- —
- KEV
- Not listed
Published
September 18, 2026
Last Modified
September 18, 2026
Advisory Details (6)
Auto-updated Sep 18, 2026No patch confirmed yet.
generic
SGLang through 0.5.20 Unbounded Memory Allocation via STAGING_REQ chunk_idx | Advisories | VulnCheck
https://www.vulncheck.com/advisories/sglang-through-0.5.20-unbounded-memory-allocation-via-staging-req-chunk-idxgeneric
[Bug] Unbounded chunk_idx in PD disaggregation staging path causes Decode scheduler OOM · Issue #39764 · sgl-project/sglang · GitHub
https://github.com/sgl-project/sglang/issues/39764generic
sglang/python/sglang/srt/disaggregation/common/staging_handler.py at v0.5.20 · sgl-project/sglang · GitHub
https://github.com/sgl-project/sglang/blob/v0.5.20/python/sglang/srt/disaggregation/common/staging_handler.py#L848-L860generic
sglang/python/sglang/srt/disaggregation/common/staging_handler.py at v0.5.20 · sgl-project/sglang · GitHub
https://github.com/sgl-project/sglang/blob/v0.5.20/python/sglang/srt/disaggregation/common/staging_handler.py#L781generic
sglang/python/sglang/srt/disaggregation/common/conn.py at v0.5.20 · sgl-project/sglang · GitHub
https://github.com/sgl-project/sglang/blob/v0.5.20/python/sglang/srt/disaggregation/common/conn.py#L1636-L1640generic
GitHub - sgl-project/sglang: SGLang is a high-performance serving framework for large language models and multimodal models. · GitHub
https://github.com/sgl-project/sglangVendor Advisories for CVE-2026-93838(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 3× in last 7d / 3× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-09-18 20:31 UTCEG score recompute
- 2026-09-18 19:19 UTCEG score recompute
- 2026-09-18 19:19 UTCMITRE cvelistV5first tracked
Frequently asked(4)
What is CVE-2026-93838?
CVE-2026-93838 is a medium vulnerability published on September 18, 2026. SGLang versions through 0.5.20 contain an unbounded memory allocation vulnerability in handlestagingreq() that fails to validate chunkidx from ZMQ STAGINGREQ frames in prefill/decode disaggregation deployments. Attackers with access to the decode engine's internal ZMQ rank port can send a frame…
When was CVE-2026-93838 disclosed?
CVE-2026-93838 was first published in the National Vulnerability Database on September 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
What is the CVSS score of CVE-2026-93838?
CVE-2026-93838 has a CVSS v3 base score of 5.9 (NVD). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-93838?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-93838, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-93838
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