# CVE-2020-6173: PYSEC-2020-146 - TUF (aka The Update Framework) 0.7.2 through 0.12.1 allows Uncontrolled Resource Consumption.

Source: https://junglewise.ai/threats/cve-2020-6173-the-update-framework-denial-of-service-in-tuf-client  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2020-01-14. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2020-6173 · Severity: low · CVSS 3.1 · Published 2020-01-14

The Update Framework (TUF) is a metadata framework used by software repositories to ensure secure package distribution. An attacker with file write access to the repository can cause client applications to experience significant delays (minutes or longer) by injecting many invalid signatures into metadata files, forcing clients to verify each one before detecting the invalidity.

Technologies: [tuf (PyPI)](https://junglewise.ai/threats/technologies/tuf). Vendors: [PyPI](https://junglewise.ai/threats/vendors/pypi).

## Quick answers

**Is CVE-2020-6173 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2020-6173 being exploited in the wild.

**How severe is CVE-2020-6173?** Low severity, with a CVSS score of 3.1, published 14 January 2020.

**Which products and versions are affected?** tuf (PyPI) ECOSYSTEM:introduced=0.7.2,fixed=0.12.2, ECOSYSTEM:introduced=0.7.5,fixed=0.12.2.

**Is there a fix for CVE-2020-6173?** Yes. tuf (PyPI): upgrade to 0.12.2 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2020-6173 attacked?** It is attacked with local access, in a software library.

**Am I affected by CVE-2020-6173?** Check whether you run tuf (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- tuf (PyPI): upgrade to 0.12.2 or later

  ```sh
  pip install "tuf>=0.12.2"
  ```


## Technical details

This vulnerability is a denial of service issue in the TUF client signature verification process (CWE-400: Uncontrolled Resource Consumption). An attacker who gains write access to the repository metadata can create metadata files with a large number of invalid signatures. The vulnerable TUF client will attempt to verify each signature sequentially, delaying the moment when it determines that all signatures are invalid. This delay can extend to minutes or longer, particularly when multiple metadata files are affected. The attack requires repository file access; no network exploitation or user interaction is needed. No patch has been released for this issue.

## Affected products

- The Update Framework TUF 0.7.2 through 0.12.1

## Identifiers

- CVE-2020-6173
- GHSA-2828-9vh6-9m6j
- PYSEC-2020-146

## Timeline

- 2020-08-21: disclosed

## References

- [https://github.com/theupdateframework/tuf/security/advisories/GHSA-2828-9vh6-9m6j](https://github.com/theupdateframework/tuf/security/advisories/GHSA-2828-9vh6-9m6j)

## Related threats

- [theupdateframework python-tuf improper case sensitivity in delegation matching](https://junglewise.ai/threats/theupdateframework-python-tuf-improper-case-sensitivity-in-delegation-4289ebd1)
- [tuf's Metadata API: Targets.get_delegated_role() is missing input validation](https://junglewise.ai/threats/tuf-s-metadata-api-targets-get-delegated-role-is-missing-input-88281f97)
- [Python-TUF vulnerable to incorrect threshold signature computation for new root metadata](https://junglewise.ai/threats/python-tuf-vulnerable-to-incorrect-threshold-signature-computation-for-042f316e)
- [Client metadata path-traversal](https://junglewise.ai/threats/cve-2021-41131-client-metadata-path-traversal)
- [Invalid root may become trusted root in The Update Framework (TUF)](https://junglewise.ai/threats/cve-2020-15163-invalid-root-may-become-trusted-root-in-the-update-framework-tuf)