Tendermint light client verification not taking into account chain IDGHSA-xqqc-c5gw-c5r5
MEDIUMFix: informalsystems/tendermint-rs@5c32f31GHSA-xqqc-c5gw-c5r5 is a medium-severity (CVSS 5.4) CWE-347 vulnerability in tendermint-light-client-verifier. A fix is available for tendermint-light-client-verifier — see the affected versions and patch details below.
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-xqqc-c5gw-c5r5.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
tendermint-light-client-verifier🦀tendermint-light-client🦀tendermint-light-client-jsReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.
Description
Tendermint is a high-performance blockchain consensus engine for Byzantine fault tolerant applications. Versions prior to 0.28.0 contain a potential attack via Improper Verification of Cryptographic Signature, affecting anyone using the tendermint-light-client and related packages to perform light client verification (e.g. IBC-rs, Hermes). The light client does not check that the chain IDs of the trusted and untrusted headers match, resulting in a possible attack vector where someone who finds a header from an untrusted chain that satisfies all other verification conditions (e.g. enough overlapping validator signatures) could fool a light client. The attack vector is currently theoretical, and no proof-of-concept exists yet to exploit it on live networks. This issue is patched in version 0.28.0. There are no workarounds.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | tendermint-light-client-verifier | all versions | 0.28.0cargo update -p tendermint-light-client-verifier --precise 0.28.0 |
| 🦀crates.io | tendermint-light-client | all versions | 0.28.0cargo update -p tendermint-light-client --precise 0.28.0 |
| 🦀crates.io | tendermint-light-client-js | all versions | 0.28.0cargo update -p tendermint-light-client-js --precise 0.28.0 |
Affected Products
tendermint-light-clienttendermint-light-client_projecttendermint-light-client-jstendermint-light-client-js_projecttendermint-light-client-verifiertendermint-light-client-verifier_projectDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for tendermint-light-client-verifier, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update tendermint-light-client-verifier to 0.28.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-xqqc-c5gw-c5r5 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Frequently Asked Questions
Is GHSA-xqqc-c5gw-c5r5 in your dependencies?
Find it across crates.io, including transitive dependencies.