Trestle has Server-Side Template Injection (SSTI) via Recursive Template Re-evaluation of Untrusted Data

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2026-54757: 0.36% estimated exploitation activity in the next 30 days; percentile 30.34 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact A Server-Side Template Injection (SSTI) vulnerability exists in multiple locations of trestle's Jinja2 rendering pipeline due to a systemic pattern: untrusted data is re-parsed as Jinja2 template source code without sandboxing. This advisory tracks the root cause across all affected code paths. The core anti-pattern is: treating runtime data (rendered output, included Markdown content, LUT values) as Jinja2 template source code and passing it to Parser.parse() or an equivalent rendering cycle, without using SandboxedEnvironment or escaping Jinja2 syntax delimiters. Because jinja2.Environment (not SandboxedEnvironment) is used, injected expressions can traverse Python object chains (class.mro, globals, subclasses()) to achieve arbitrary command execution via os.system() or subprocess. Previously fixed instance (historical context): An earlier version of rendertemplate() in trestle/core/commands/author/jinja.py implemented a recursive while loop: rendered output was loaded via…

Published by the source

28 Aug 2026, 16:15 UTC

Last modified by the source

28 Aug 2026, 16:15 UTC

Source last checked

26 Oct 2026, 13:50 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-jw39-3688-r4rx

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# Patch Next advisory brief: CVE-2026-54757

Advisory: Trestle has Server-Side Template Injection (SSTI) via Recursive Template Re-evaluation of Untrusted Data
IDs: CVE-2026-54757, GHSA-jw39-3688-r4rx
Record: https://patchnext.com/advisories/cve-2026-54757 (revision 1, source checked 26 Oct 2026, 13:50 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: compliance-trestle 4.1.0, 3.12.4. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI compliance-trestle: affected <= 3.12.3; >= 4.0.0, < 4.1.0; fixed in 3.12.4, 4.1.0

## Suggested inspection (read-only)
- `python -m pip show compliance-trestle`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on compliance-trestle.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-jw39-3688-r4rx (GitHub-reviewed advisory GHSA-jw39-3688-r4rx lists affected ranges: PyPI compliance-trestle >=0 =4.0.0 <4.1.0)

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