Markdown-supplied Shell Command Execution

Exploitation

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

CVSS 4.0

9.3 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N · score source

EPSS

• CVE-2020-15271: 2.31% estimated exploitation activity in the next 30 days; percentile 83.40 (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 lookatme versions prior to 2.3.0 automatically loaded the built-in "terminal" and "fileloader" extensions. Users that use lookatme to render untrusted markdown may have malicious shell commands automatically run on their system. Patches Users should upgrade to lookatme versions 2.3.0 or above. Workarounds The lookatme/contrib/terminal.py and lookatme/contrib/fileloader.py files may be manually deleted. Additionally, it is always recommended to be aware of what is being rendered with lookatme. References https://github.com/d0c-s4vage/lookatme/pull/110 https://github.com/d0c-s4vage/lookatme/releases/tag/v2.3.0 For more information If you have any questions or comments about this advisory: Open an issue in d0c-s4vage/lookatme

Published by the source

27 Oct 2020, 17:59 UTC

Last modified by the source

10 Sep 2026, 03:48 UTC

Source last checked

26 Oct 2026, 13:21 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-c84h-w6cr-5v8q

2. Revision 2 · amended · 24 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-c84h-w6cr-5v8q

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# Patch Next advisory brief: CVE-2020-15271

Advisory: Markdown-supplied Shell Command Execution
IDs: CVE-2020-15271, GHSA-c84h-w6cr-5v8q
Record: https://patchnext.com/advisories/cve-2020-15271 (revision 3, source checked 26 Oct 2026, 13:21 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: lookatme 2.3.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI lookatme: affected < 2.3.0; fixed in 2.3.0

## Suggested inspection (read-only)
- `python -m pip show lookatme`: 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 lookatme.
- 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://osv.dev/vulnerability/GHSA-c84h-w6cr-5v8q (OSV record GHSA-c84h-w6cr-5v8q lists affected ranges: PyPI lookatme >=0 <2.3.0 (fixed))
- Verified: https://github.com/advisories/GHSA-c84h-w6cr-5v8q (GitHub-reviewed advisory GHSA-c84h-w6cr-5v8q lists affected ranges: PyPI lookatme >=0 <2.3.0)

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