Cyber Resilience

CVE-2026-5760

RCE in Lmsys Sglang ≤ 0.5.11

Public PoCRCE
Published
20 April 2026
Modified
03 June 2026
Patch / advisory
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0085 55th percentile
Risk Priority 73 floored blend · peak EPSS

Summary

CVE-2026-5760 is a critical-severity Code Injection (CWE-94) vulnerability in Lmsys Sglang. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Command and Scripting Interpreter (T1059); ranked in the top 45% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2026-5760, published on 2026-04-20, is a critical vulnerability (CVSS 9.8, CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H) affecting SGLang's reranking endpoint (/v1/rerank). It enables remote code execution (RCE) when a model file containing a malicious tokenizer.chat_template is loaded, as Jinja2 chat templates are rendered using an unsandboxed jinja2.Environment(). The issue is classified under CWE-94 (code injection).

An unauthenticated attacker with network access can exploit the vulnerability with low attack complexity and no user interaction. By triggering the loading of a model file with a malicious chat template via the reranking endpoint, the attacker achieves arbitrary remote code execution, compromising confidentiality, integrity, and availability to a high degree.

Mitigation details are available in related advisories, including the GitHub proof-of-concept repository at https://github.com/Stuub/SGLang-0.5.9-RCE and the CERT vulnerability note at https://www.kb.cert.org/vuls/id/915947.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

SGLang's reranking endpoint (/v1/rerank) achieves Remote Code Execution (RCE) when a model file containing a malcious tokenizer.chat_template is loaded, as the Jinja2 chat templates are rendered using an unsandboxed jinja2.Environment().

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1059 Command and Scripting Interpreter Execution
Adversaries may abuse command and script interpreters to execute commands, scripts, or binaries.
T1059.001 PowerShell Execution
Adversaries may abuse PowerShell commands and scripts for execution.
T1059.002 AppleScript Execution
Adversaries may abuse AppleScript for execution.
T1059.004 Unix Shell Execution
Adversaries may abuse Unix shell commands and scripts for execution.
T1059.005 Visual Basic Execution
Adversaries may abuse Visual Basic (VB) for execution.
T1059.006 Python Execution
Adversaries may abuse Python commands and scripts for execution.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-15971Same product: Lmsys Sglang
CVE-2026-3989Same product: Lmsys Sglang
CVE-2026-3060Same product: Lmsys Sglang
CVE-2026-3059Same product: Lmsys Sglang
CVE-2026-7301Same product: Lmsys Sglang
CVE-2026-14890Same product: Lmsys Sglang
CVE-2026-15969Same product: Lmsys Sglang
CVE-2026-7304Same product: Lmsys Sglang
CVE-2026-10775Same product: Lmsys Sglang
CVE-2026-15978Same product: Lmsys Sglang

Affected Assets

lmsys
sglang
≤ 0.5.11

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V1.3.1

Mitigating Controls (NIST 800-53 r5) AI

Developer testing and evaluation finds code paths that accept and execute externally influenced strings.

Input validation directly stops untrusted data from being used to construct executable code without neutralization.

Least privilege limits the damage an injected code fragment can perform once executed.

Requiring documented secure development standards and tools enforces use of safe code-generation APIs and escaping.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

PR.PS-06's SDLC practices directly target injection flaws via secure coding and testing (mostly), yet as a single broad outcome it leaves many code-generation specifics unaddressed (partial).

PR.DS-10 none match
prevents

PR.DS-10 protects runtime data confidentiality/integrity but has no bearing on neutralizing externally influenced input during code generation, so neither direction shows any preventive effect.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

prevents

Banning unapproved code samples and unauthenticated web services, combined with secure-coding standards and SAST, prevents the dynamic generation or inclusion of attacker-supplied code.

none

Controls that restrict unauthorized or malicious code from being introduced via external networks or removable media limit opportunities for an attacker to inject and execute arbitrary code.

References