CVE-2026-15978

Analyzed Analyzed - Analysis Complete

Model Weight Exfiltration in SGLang Without API Keys

Publication date: 2026-07-30

Last updated on: 2026-08-04

Assigner: CERT/CC

Description

SGLang contains a model weight exfiltration vulnerability when no API keys are configured, as SGLang will expose two endpoints that allow a remote attacker to trigger distributed weight broadcasting using NCCL and then triggering data transfer, attackers can exfiltrate all model weights.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-07-30

Last Modified

2026-08-04

Generated

2026-08-20

AI Q&A

2026-07-31

EPSS Evaluated

2026-08-18

NVD

CVE-2026-15978

EUVD

EUVD-2026-51266

Affected Vendors & Products

Vendor	Product	Version / Range
lmsys	sglang	to 0.5.15 (inc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-306	The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.

Attack-Flow Graph

Executive Summary

SGLang has a vulnerability where model weights can be stolen if no API keys are set. Attackers can access two endpoints to trigger weight broadcasting via NCCL and force data transfer, allowing them to steal all model weights remotely.

Impact Analysis

If you use SGLang without API keys, attackers could steal your model weights, leading to loss of proprietary data, intellectual property theft, or unauthorized use of your models. This could disrupt operations or enable further attacks.

Compliance Impact

This vulnerability could violate data protection regulations like GDPR or HIPAA if model weights contain sensitive or personal data. Unauthorized exfiltration may lead to compliance breaches, legal penalties, or reputational damage.

Mitigation Strategies

Configure API keys in SGLang to restrict access to sensitive endpoints. Disable NCCL-based weight broadcasting if not required. Monitor network traffic for unusual data transfers from SGLang processes.

Hi! I’m here to help you understand CVE-2026-15978. Ask me anything about the vulnerability, its impact, or mitigation strategies.

0/70