# CVE-2025-59941: go-f3 is Vulnerable to Cached Justification Verification Bypass

> An attacker can bypass justification verification in go-f3 by reusing cached verification results across different message contexts.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 29 Sep 2025
- **Updated:** 30 Sep 2025
- **Also known as:** GHSA-7pq9-rf9p-wcrf, GO-2025-3989

## What is CVE-2025-59941?

CVE-2025-59941 is a medium-severity vulnerability in filecoin-project go-f3, published on 29 Sep 2025. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

go-f3 is a Golang implementation of Fast Finality for Filecoin (F3). In versions 0.8.8 and below, go-f3's justification verification caching mechanism has a vulnerability where verification results are cached without properly considering the context of the message. An attacker can bypass justification verification by submitting a valid message with a correct justification and then reusing the same cached justification in contexts where it would normally be invalid. This occurs because the cached verification does not properly validate the relationship between the justification and the specific message context it's being used with. This issue is fixed in version 0.8.9.

Weakness: CWE-305 (Authentication Bypass by Primary Weakness)

## Which versions are affected by CVE-2025-59941?

3 open source packages ship an affected version, including github.com/filecoin-project/go-f3. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/filecoin-project/go-f3` | Go | All versions | 0.8.9 |
| `github.com/filecoin-project/go-f3` | Go | All versions | 0.8.9 |
| `github.com/filecoin-project/go-f3` | Go | All versions | 0.8.9 |

Products: Filecoin Go-F3.

## How do I fix CVE-2025-59941?

Upgrade github.com/filecoin-project/go-f3 to 0.8.9 or later.

## Is CVE-2025-59941 being exploited?

There is no known exploitation of CVE-2025-59941 in the wild and no public exploit code.

## Other vulnerabilities in filecoin-project go-f3

- [CVE-2025-59942](https://insights.sbomify.com/CVE-2025-59942/): go-f3 module vulnerable to integer overflow leading to panic (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-59941 and fix it if it is affected.

What it is: CVE-2025-59941 is a medium-severity vulnerability in filecoin-project go-f3, published on 29 Sep 2025. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-59941 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/filecoin-project/go-f3 (Go): affected all versions; fixed in 0.8.9
- github.com/filecoin-project/go-f3 (Go): affected all versions; fixed in 0.8.9
- github.com/filecoin-project/go-f3 (Go): affected all versions; fixed in 0.8.9

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/CVE-2025-59941/ (Markdown: https://insights.sbomify.com/CVE-2025-59941/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-59941
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-59941
- OSV: https://osv.dev/vulnerability/CVE-2025-59941

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-59941/
Summaries are generated and may contain mistakes; the official description above is the record.