GHSA-f8mr-jv2c-v8mg is a high-severity (CVSS 8.7) CWE-863 vulnerability in tuf. A fix is available for tuf — see the affected versions and patch details below.
Invalid root may become trusted root in The Update Framework (TUF)
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-f8mr-jv2c-v8mg plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,166 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
tufReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Impact
The Python TUF reference implementation tuf<0.12 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 man-in-the-middle attack) culminating in a version which has not been correctly signed to control the trust chain for future updates.
While investigating the reported vulnerability, we discovered that the detailed client workflow was not fully implemented. Specifically, for step 1.3 the newly downloaded root metadata was not being verified with a threshold of keys specified in the new root metadata file. This missing step of the client workflow has been implemented in PR #1101, which is included in v0.14.0 of tuf.
Patches
A fix, is available in version 0.12 and newer.
Workarounds
No workarounds are known for this issue.
References
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | tuf | all versions | 0.12.0pip install --upgrade 'tuf==0.12.0' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for tuf, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update tuf to 0.12.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-f8mr-jv2c-v8mg is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-f8mr-jv2c-v8mg can be triaged on real exposure rather than presence alone.
Tailored to GHSA-f8mr-jv2c-v8mg. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-f8mr-jv2c-v8mg in your dependencies?
O3 Security finds GHSA-f8mr-jv2c-v8mg across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.