CVE-2021-41135 is a medium-severity (CVSS 6.5) CWE-754 vulnerability in github.com/cosmos/cosmos-sdk. 1 public exploit reference exists, so weaponization risk is real. A fix is available for github.com/cosmos/cosmos-sdk — see the affected versions and patch details below.
Authz Module Non-Determinism
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2021-41135 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
github.com/cosmos/cosmos-sdkReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
The Cosmos-SDK is a framework for building blockchain applications in Golang. Affected versions of the SDK were vulnerable to a consensus halt due to non-deterministic behaviour in a ValidateBasic method in the x/authz module. The MsgGrant of the x/authz module contains a Grant field which includes a user-defined expiration time for when the authorization grant expires. In Grant.ValidateBasic(), that time is compared to the node’s local clock time. Any chain running an affected version of the SDK with the authz module enabled could be halted by anyone with the ability to send transactions on that chain. Recovery would require applying the patch and rolling back the latest block. Users are advised to update to version 0.44.2.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/cosmos/cosmos-sdk | ≥ 0.43.0&&< 0.44.2 | 0.44.2go get github.com/cosmos/cosmos-sdk@v0.44.2 |
Affected Products
cosmos sdkinterchainResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/cosmos/cosmos-sdk, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/cosmos/cosmos-sdk to 0.44.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-41135 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 CVE-2021-41135 in your dependencies?
Find it across Go, including transitive dependencies.