CVE-2026-15969: sglang Insecure Deserialization (CVSS 9.8)

Description

SGLang contains an unauthenticated RCE in /load_lora_adapter_from_tensors via bypass of SafeUnpickler’s incomplete denylist, allowing arbitrary command execution through crafted base64-encoded pickle payloads.

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CVSS v3.1 Score

9.8

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0138

Probability of exploitation

0.70%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-502 Deserialization of Untrusted Data

Affected Products

Vendor	Product	Versions
lmsys	sglang	< 0.5.15

References

Other References

https://github.com/sgl-project/sglang/security/advisories/GHSA-2wvm-gjg7-5jfm https://thoughts.apoorvdayal.com/posts/sglang-disclosures/

Frequently Asked Questions

What is CVE-2026-15969? +

SGLang contains an unauthenticated RCE in /load_lora_adapter_from_tensors via bypass of SafeUnpickler’s incomplete denylist, allowing arbitrary command execution through crafted base64-encoded pickle payloads. It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2026-15969? +

CVE-2026-15969 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0138, placing it in the 1th percentile for exploitation probability.

What products are affected by CVE-2026-15969? +

CVE-2026-15969 affects products from lmsys, specifically: sglang. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-15969? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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