Is CVE-2026-86793 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-86793 being exploited in the wild.

How severe is CVE-2026-86793?

Critical severity, with a CVSS score of 9.8, published 11 September 2026.

Is there a fix for CVE-2026-86793?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-86793 attacked?

It is attacked over the network.

Am I affected by CVE-2026-86793?

Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-86793: SGLang unsafe pickle deserialization in /update_weights_from_tensor

CVE-2026-86793 · Severity: critical · CVSS 9.8 · Published 2026-09-11

SGLang is an open-source framework for deploying large language models. The /update_weights_from_tensor endpoint allows unauthenticated attackers to send crafted pickle-serialized data when no API keys are configured. By exploiting bypasses in the SafeUnpickler safety mechanism, an attacker can execute arbitrary code on the SGLang server, potentially compromising all models and data processed by it.

Quick answers

Is CVE-2026-86793 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-86793 being exploited in the wild.
How severe is CVE-2026-86793?: Critical severity, with a CVSS score of 9.8, published 11 September 2026.
Which products and versions are affected?: SGLang SGLang.
Is there a fix for CVE-2026-86793?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-86793 attacked?: It is attacked over the network.
Am I affected by CVE-2026-86793?: Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The vulnerability is a pickle deserialization attack (CWE-502) in SGLang's SafeUnpickler implementation. The SafeUnpickler was introduced to mitigate CVE-2025-10164 but has flawed logic: its allowlist includes the broad "builtins." prefix, and its denylist omits __import__ and getattr. An attacker can chain these permitted builtins functions to construct a gadget chain that reaches os.system or other dangerous functions. The /update_weights_from_tensor endpoint at the HTTP server (python/sglang/srt/entrypoints/http_server.py) accepts base64-encoded pickle payloads with AuthLevel.ADMIN_OPTIONAL, making it unauthenticated when no keys are configured. When the payload is deserialized, the GLOBAL pickle opcode triggers find_class(), which fails to block the __import__/__getattr__ gadget chain, leading to remote code execution.

Affected products

SGLang SGLang

Timeline

2026-09-11: disclosed

References

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.