# Invalid root may become trusted root in The Update Framework (TUF)

Advisory record · `GHSA-f8mr-jv2c-v8mg`

- **Identifiers:** `GHSA-f8mr-jv2c-v8mg` · `CVE-2020-15163` · `PYSEC-2020-145`
- **State:** Confirmed
- **Severity:** CVSS 8.7 High
- **Critical:** No
- **Weakness (CWE):** [CWE-345](https://cwe.mitre.org/data/definitions/345.html) · [CWE-863](https://cwe.mitre.org/data/definitions/863.html)
- **Tags:** [Broken access control](https://agentprime.io/advisories/tag/access-control.md) · [CWE-345](https://agentprime.io/advisories/tag/cwe-345.md)
- **Published:** 9 Sept 2020
- **Updated:** 10 Sept 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 9 Sept 2020, 17:29 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `tuf` (PyPI): affected `<0.12.0`; fixed in `0.12.0`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> The Python tuf package, versions before 0.12.0, will trust a previously downloaded root metadata file that failed verification at download time. An attacker who can intercept and serve several successive new root metadata versions, such as through a man-in-the-middle attack, can end with an improperly signed version that then controls the trust chain for future updates. Upgrade to tuf 0.12.0 or newer; no workarounds are known.

Written 5 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 8.7 High, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0067, the 52nd percentile, on 12 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:38 UTC: First seen by agentprime
- 31 Oct 2026, 14:38 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-f8mr-jv2c-v8mg)

## Sources

- [GitHub Advisory Database: GHSA-f8mr-jv2c-v8mg](https://github.com/advisories/GHSA-f8mr-jv2c-v8mg)
- [OSV: GHSA-f8mr-jv2c-v8mg](https://osv.dev/vulnerability/GHSA-f8mr-jv2c-v8mg)
- <https://github.com/theupdateframework/tuf/security/advisories/GHSA-f8mr-jv2c-v8mg>
- <https://nvd.nist.gov/vuln/detail/CVE-2020-15163>
- <https://github.com/theupdateframework/tuf/pull/885>
- <https://github.com/theupdateframework/tuf/commit/3d342e648fbacdf43a13d7ba8886aaaf07334af7>
- <https://github.com/pypa/advisory-database/tree/main/vulns/tuf/PYSEC-2020-145.yaml>
- <https://github.com/theupdateframework/tuf>
- <https://github.com/theupdateframework/tuf/releases/tag/v0.12.0>
- <https://pypi.org/project/tuf>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-f8mr-jv2c-v8mg>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-f8mr-jv2c-v8mg/>. Everything for agents: <https://agentprime.io/llms.txt>.