CVE-2026-54757

Server‑side template injection in Trestle Jinja2 tags enables remote code execution.

• CVSS 7.8
• 94
• Input Validation and Sanitization
• Remote

Compliance-trestle (Trestle) is a Python SDK and command-line tool for managing OSCAL compliance documents. In versions before 3.12.4 and versions 4.0.0 through 4.0.3, Trestle is vulnerable to server-side template injection that can lead to remote code execution. This occurs because the MDCleanInclude and MDSectionInclude Jinja2 tags re-parse untrusted Markdown content as template source code using a non-sandboxed jinja2.Environment. An attacker who controls content that Trestle renders, such as a crafted workspace Markdown file, a third-party SSP document, or a YAML lookup-table value, can inject a Jinja2 expression that traverses Python object internals to execute arbitrary operating system commands in the context of the Trestle process. This issue is fixed in versions 3.12.4 and 4.1.0.

CVE

CVE-2026-54757

CWE

94

CVSS base score

7.8

Published

2026-08-25

OWASP

A04 Injection

Orthogonal defect classification

Checking

Code defect classification

Incorrect Check

Category

Input Validation and Sanitization

Subcategory

Command Injection

Accessibility scope

Remote

Impact

Arbitrary Code Execution

Affected component

Python

Fixed by upgrading

Yes

Solution

Upgrade Trestle to 3.12.4 or later (or to 4.1.0 or later).

import jinja2

def render_markdown(md_text: str) -> str:
    # VULNERABLE: unsandboxed Jinja2 environment allows template injection
    env = jinja2.Environment()
    template = env.from_string(md_text)
    return template.render()

import jinja2
from jinja2.sandbox import SandboxedEnvironment

def render_markdown(md_text: str) -> str:
    # FIX: use sandboxed environment to prevent template injection
    env = SandboxedEnvironment()
    template = env.from_string(md_text)
    return template.render()

__VAITP_MODEL_REFUSED__

@misc{vaitp:cve202654757,
  title        = {{Server‑side template injection in Trestle Jinja2 tags enables remote code execution.}},
  author       = {Bogaerts, Fr\'ed\'eric and Ivaki, Naghmeh and Fonseca, Jos\'e},
  year         = {2026},
  note         = {VAITP Python Vulnerability Dataset, entry CVE-2026-54757},
  howpublished = {\url{https://netpack.pt/vaitp/vulnerability/CVE-2026-54757/}}
}