CVE-2026-86793

SGLang · SGLang

SGLang is vulnerable to unauthenticated pickle deserialization, allowing remote code execution via the /update_weights_from_tensor endpoint when authentication keys are not configured.

Executive summary

An unauthenticated remote code execution vulnerability in SGLang poses a critical risk to AI infrastructure by allowing attackers to bypass deserialization protections.

Vulnerability

This flaw involves improper control of code generation (CWE-94) via insecure pickle deserialization. An unauthenticated attacker can trigger the execution of arbitrary code by exploiting a bypass in the SafeUnpickler policy, which incorrectly allows the resolution of dangerous built-in functions.

Business impact

The ability for an unauthenticated user to execute arbitrary code on a server hosting SGLang represents a total compromise of the affected system. Given the CVSS score of 9.8, this vulnerability allows for complete data exfiltration, modification of AI model weights, and full system takeover, which could lead to significant operational disruption and loss of proprietary research data.

Remediation

Immediate Action: Ensure all SGLang instances are configured with robust authentication keys, and monitor for updates from the project maintainers to address the underlying pickle deserialization flaw.

Proactive Monitoring: Review web server access logs for suspicious requests targeting the /update_weights_from_tensor endpoint, particularly those originating from unauthorized IP addresses.

Compensating Controls: Implement strict network segmentation and egress filtering to prevent compromised AI servers from communicating with malicious external command and control infrastructure.

Exploitation status

Public Exploit Available: Unknown

Analyst recommendation

Given the critical nature of this vulnerability and the potential for total system compromise, organizations running SGLang must prioritize the configuration of authentication keys immediately. If authentication cannot be guaranteed, the service should be isolated from public network access until a security patch is released and applied to remediate the deserialization flaw.

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History

CVE Brief tracked this CVE 4 days before it had a CVSS score.

  1. Disclosed CVE record published
  2. Collected by CVE Brief No CVSS score yet; tracked as early warning
  3. CVSS score assigned 9.8 (3.1)
  4. Analyst report written

Sources