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CVE-2025-59941

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

5.9

CVSS Score
3.1

Basic Information

CVE ID
CVE-2025-59941
GHSA ID
GHSA-7pq9-rf9p-wcrf
EPSS Score
-
CWE
CWE-305
Published
9/29/2025
Updated
9/29/2025
KEV Status
No
Technology
TechnologyGo

Technical Details

CVSS Vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:L
Package NameEcosystemVulnerable VersionsFirst Patched Version
github.com/filecoin-project/go-f3go< 0.8.90.8.9

Vulnerability Intelligence
Miggo AIMiggo AI

Miggo AIRoot Cause Analysis

The vulnerability, identified as GHSA-7pq9-rf9p-wcrf, is a caching issue within the go-f3 library's justification verification process. The root cause is that the caching mechanism for validation results did not properly account for the message context.

The function cachingValidator.validateJustification in gpbft/validator.go was using a cache key for justifications that was generated only from the content of the justification itself. The cachingValidator.getCacheKey function was responsible for this behavior. Consequently, if a justification was validated once in a correct context, its validation result would be cached. An attacker could then reuse this same justification in a different, invalid context (e.g., for a different message value). The system would find the cached result based on the justification's hash and incorrectly skip the full validation, leading to the acceptance of an invalid message.

The patch addresses this by making the cache key more specific. It modifies cachingValidator.getCacheKey to accept additional data. The cachingValidator.validateJustification function is updated to pass the expectedVoteValueKey (a key derived from the value being voted on in the message) to getCacheKey. This ensures that the cache key is now a composite of the justification and the context in which it is used, effectively preventing the reuse of cached validations across different contexts and closing the vulnerability.

Vulnerable functions

cachingValidator.validateJustification
gpbft/validator.go
This function is responsible for validating justifications for messages in the consensus protocol. The vulnerability lies in its caching mechanism. It previously cached the validation result of a justification using a key that only depended on the justification itself, not the specific message or value it was justifying. This allowed an attacker to submit a message with a valid justification, have its validation result cached, and then reuse that same justification for a different, malicious message, bypassing the actual validation logic due to the cache hit.
cachingValidator.getCacheKey
gpbft/validator.go
This helper function generates the key used for caching validation results. The original implementation created a key based solely on the CBOR-marshaled justification object. This was the root cause of the vulnerability, as it failed to create a unique key for each validation context. The patch rectifies this by allowing additional data (specifically, the `expectedVoteValueKey` from the message being validated) to be appended to the key, thus ensuring the cache key is unique to the justification and its context.

WAF Protection Rules

WAF Rule

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Reasoning

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