CVE-2026-54757: Trestle has Server-Side Template Injection (SSTI) via Recursive Template Re-evaluation of Untrusted Data
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.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 3.12.4 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 4.1.0
Event History
Frequently Asked Questions
Which Trestle releases require remediation?
Versions before 3.12.4 and versions 4.0.0 through 4.0.3 are affected. Upgrade to 3.12.4 or 4.1.0.
What access does an attacker need to exploit this issue?
The attack vector is local and requires no privileges, but it requires user interaction. Exploitation depends on the attacker being able to supply content that Trestle renders, such as a workspace Markdown file, a third-party SSP document, or a YAML lookup-table value.
How can I determine whether an environment is exposed?
Check the installed Trestle version and whether the environment renders untrusted or externally supplied Markdown, SSP documents, or YAML lookup-table values. Systems on affected versions that process such content should be treated as exposed.