GHSA-6jrf-4jv4-r9mw: Tendermint light client verifier Tendermint-rs's Light Client Verifier Allows Vulnerability

HIGH
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CWE-863
Published
Advisory Summary

GHSA-6jrf-4jv4-r9mw is a HIGH tendermint-rs's light client verifier allows vulnerability (CWE-863: Incorrect Authorization) affecting Tendermint light client verifier libraries in the crates.io ecosystem. The issue involves tendermint-rs's light client verifier allows malicious validators to spoof votes from other validators. Remediation is available by upgrading affected packages to version 0.40.3.

GHSA-6jrf-4jv4-r9mw at a Glance

CVE Identifier N/A
GHSA Identifier GHSA-6jrf-4jv4-r9mw
Severity HIGH
CVSS v3.1 Base Score N/A
CWE Classification CWE-863: Incorrect Authorization
Affected Product Tendermint light client verifier
Package Ecosystem crates.io
Published Date
Last Updated

How to Fix GHSA-6jrf-4jv4-r9mw

To remediate this vulnerability, upgrade all affected Tendermint light client verifier dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

tendermint-light-client-verifier fixed: 0.40.3 
Upgrade tendermint-light-client-verifier to 0.40.3
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for tendermint-light-client-verifier

How to Check if You Are Affected

To determine whether your application is affected by GHSA-6jrf-4jv4-r9mw, inspect your project dependencies for Tendermint light client verifier:

inspect dependencies for tendermint-light-client-verifier

Analyze the terminal output to locate any version of Tendermint light client verifier in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.40.3), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-863: Incorrect Authorization, where the product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check. In Tendermint light client verifier, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

Name: ISA-2025-003: Malicious validator can spoof votes from other validators Component: tendermint-rs Criticality: High (Catastrophic Impact; Rare Likelihood per [ACMv1.2](https://github.com/interchainio/security/blob/main/resources/CLASSIFICATION_MATRIX.md)) Affected versions: <= v0.40.2 Affected users: Everyone ### Description tendermint-rs contains a critical vulnerability in its light client implementation due to insecure handling of corrupted validator sets. Because it doesn't check that the validator address is correctly derived from the validator's public key when counting votes, it is possible to spoof votes from other validators. The result is being able to construct the malicious block and cheat the light client. The light client will accept such a block, seemingly signed by 2/3+ majority. ### Patches The new tendermint-rs release [v0.40.3](https://github.com/informalsystems/tendermint-rs/releases/tag/v0.40.3) fixes this issue. Unreleased code in the main branch is patched as well. ### Workarounds There are no known workarounds for this issue. ### Timeline * March 12, 2025, 13:41pm PST: Issue reported * March 12, 2025, 03:00am PST: Core team completes validation of issue This issue was reported by Felix Wilhelm from [Asymmetric Research](https://www.asymmetric.re/).

GHSA-6jrf-4jv4-r9mw Affected Tendermint light client verifier Versions

1 component(s)
Fixed Versions:
0.40.3
Product / Package Ecosystem Affected Versions Fixed Version
tendermint-light-client-verifier
 crates.io
< 0.40.3
0.40.3

References

GitHub Advisory / Wiki ADVISORY
https://github.com/informalsystems/tendermint-rs/security/advisories/GHSA-6jrf-4jv4-r9mw
Security Fix Commit FIX COMMIT
https://github.com/informalsystems/tendermint-rs/commit/1aabcfe6a3c0678db22097543f7f7a662f0db34b
Tendermint light client verifier Source Repository REPOSITORY
https://github.com/informalsystems/tendermint-rs

Frequently Asked Questions

What is GHSA-6jrf-4jv4-r9mw?
GHSA-6jrf-4jv4-r9mw is a security vulnerability in Tendermint light client verifier involving tendermint-rs's Light Client Verifier allows malicious validators to spoof votes from other validators under CWE-863: Incorrect Authorization.
Which Tendermint light client verifier versions are affected?
Affected versions include releases prior to 0.40.3 across affected packages: tendermint-light-client-verifier.
What version fixes GHSA-6jrf-4jv4-r9mw?
Upgrading to 0.40.3 (or the latest patched release for your respective branch) resolves the vulnerability.
Is tendermint-light-client-verifier affected?
Yes, tendermint-light-client-verifier is affected in releases prior to 0.40.3. Upgrade your dependency to 0.40.3 or later.
What CWE is associated with GHSA-6jrf-4jv4-r9mw?
GHSA-6jrf-4jv4-r9mw is classified under CWE-863: Incorrect Authorization (The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.).
How can I check crates.io dependencies for GHSA-6jrf-4jv4-r9mw?
Run the dependency tree command: 'inspect dependencies for tendermint-light-client-verifier'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-6jrf-4jv4-r9mw",
  "modified" : "2025-04-09T13:01:26Z",
  "published" : "2025-04-09T13:01:26Z",
  "aliases" : [ ],
  "summary" : "tendermint-rs's Light Client Verifier allows malicious validators to spoof votes from other validators ",
  "details" : "Name: ISA-2025-003: Malicious validator can spoof votes from other validators \nComponent: tendermint-rs\nCriticality: High (Catastrophic Impact; Rare Likelihood per [ACMv1.2](https://github.com/interchainio/security/blob/main/resources/CLASSIFICATION_MATRIX.md))\nAffected versions: <= v0.40.2\nAffected users: Everyone\n\n### Description\n\ntendermint-rs contains a critical vulnerability in its light client implementation due to insecure handling of corrupted validator sets. Because it doesn't check that the validator address is correctly derived from the validator's public key when counting votes, it is possible to spoof votes from other validators. The result is being able to construct the malicious block and cheat the light client. The light client will accept such a block, seemingly signed by 2/3+ majority.\n\n### Patches\n\nThe new tendermint-rs release [v0.40.3](https://github.com/informalsystems/tendermint-rs/releases/tag/v0.40.3) fixes this issue.\n\nUnreleased code in the main branch is patched as well.\n\n### Workarounds\n\nThere are no known workarounds for this issue.\n\n### Timeline\n\n* March 12, 2025, 13:41pm PST: Issue reported\n* March 12, 2025, 03:00am PST: Core team completes validation of issue\n\nThis issue was reported by Felix Wilhelm from [Asymmetric Research](https://www.asymmetric.re/).",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "tendermint-light-client-verifier"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.40.3"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/informalsystems/tendermint-rs/security/advisories/GHSA-6jrf-4jv4-r9mw"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/informalsystems/tendermint-rs/commit/1aabcfe6a3c0678db22097543f7f7a662f0db34b"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/informalsystems/tendermint-rs"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-863" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-04-09T13:01:26Z",
    "nvd_published_at" : null
  }
}