# GHSA-j8x2-777p-23fc: tough cyclic delegation graphs are not detected

> A TUF client library fails to detect cyclic delegations, causing stack exhaustion and process abort when processing malicious repositories.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 28 Mar 2025

## What is GHSA-j8x2-777p-23fc?

GHSA-j8x2-777p-23fc is a denial of service vulnerability in tough, published on 28 Mar 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

## Summary

In a TUF repository, the targets role’s signature indicates which target files are trusted by clients. The role can delegate full or partial trust to other roles, meaning that that role is trusted to sign target file metadata. Delegated roles can further delegate trust to other delegated roles. When searching for metadata about a given target, tough failed to detect cyclical role delegations.

## Impact

When interacting with TUF repositories which contain cyclical role delegations, tough will fail to detect the cycles and will exhaust its stack while recursively searching the delegation graph. The exhausted call stack will cause the process to abort.

Impacted versions: < v0.20.0

## Patches

A fix for this issue is available in tough version 0.20.0 and later. Customers are advised to upgrade to version 0.20.0 or later and ensure any forked or derivative code is patched to incorporate the new fixes.

## Workarounds

There is no recommended work around. Customers are advised to upgrade to version 0.20.0 or the latest version.

## References

If you have any questions or comments about this advisory we ask that you contact AWS/Amazon Security via our vulnerability reporting page [1] or directly via email to [aws-security@amazon.com](mailto:aws-security@amazon.com). Please do not create a public GitHub issue.

[1] Vulnerability reporting page: https://aws.amazon.com/security/vulnerability-reporting

## Acknowledgement

These issues were identified by the [TUF-Conformance project](https://github.com/theupdateframework/tuf-conformance). We would like to thank Google for collaborating on this issue through the coordinated vulnerability disclosure process.

## Which versions are affected by GHSA-j8x2-777p-23fc?

2 open source packages ship an affected version, including tough.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `tough` | crates.io | All versions | 0.20.0 |
| `tough` | crates.io | All versions | 0.20.0 |

## How do I fix GHSA-j8x2-777p-23fc?

Upgrade tough to 0.20.0 or later.

## Is GHSA-j8x2-777p-23fc being exploited?

There is no known exploitation of GHSA-j8x2-777p-23fc in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for GHSA-j8x2-777p-23fc and fix it if it is affected.

What it is: GHSA-j8x2-777p-23fc is a denial of service vulnerability in tough, published on 28 Mar 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of GHSA-j8x2-777p-23fc in the wild and no public exploit code.

Affected packages and fixed versions:
- tough (crates.io): affected all versions; fixed in 0.20.0
- tough (crates.io): affected all versions; fixed in 0.20.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/GHSA-j8x2-777p-23fc/ (Markdown: https://insights.sbomify.com/GHSA-j8x2-777p-23fc/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/GHSA-j8x2-777p-23fc

---
From sbomify Insights: https://insights.sbomify.com/GHSA-j8x2-777p-23fc/
Summaries are generated and may contain mistakes; the official description above is the record.