CVE-2021-4238 is a critical-severity (CVSS 9.1) CWE-331 vulnerability in github.com/Masterminds/goutils. 1 public exploit reference exists, so weaponization risk is real. A fix is available for github.com/Masterminds/goutils — see the affected versions and patch details below.
Duplicate Advisory: GoUtils's randomly-generated alphanumeric strings contain significantly less entropy than expected
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
- 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 CVE-2021-4238.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2021-4238 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,987 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/Masterminds/goutilsReal-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
Duplicate Advisory
This advisory has been withdrawn because it is a duplicate of GHSA-xg2h-wx96-xgxr. This link is maintained to preserve external references.
Original Description
Randomly-generated alphanumeric strings contain significantly less entropy than expected. The RandomAlphaNumeric and CryptoRandomAlphaNumeric functions always return strings containing at least one digit from 0 to 9. This significantly reduces the amount of entropy in short strings generated by these functions.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/Masterminds/goutils | all versions | 1.1.1go get github.com/Masterminds/goutils@v1.1.1 |
Affected Products
goutilsgoutils_projectResearch 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/Masterminds/goutils, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/Masterminds/goutils to 1.1.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-4238 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.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
| Product | Fixed in | Advisory |
|---|---|---|
| OpenShift Service Mesh 2.1 | servicemesh-0:2.1.6-1.el8 | RHSA-2023:0540 |
| Red Hat OpenShift Container Platform 4.10 | openshift4/ose-cluster-network-operator:v4.10.0-202301310115.p0.gdc0a59a.assembly.stream | RHSA-2023:0561 |
| Red Hat OpenShift Container Platform 4.10 | openshift4/ose-installer:v4.10.0-202302161028.p0.g8862860.assembly.stream | RHSA-2023:0899 |
| Red Hat OpenShift Container Platform 4.10 | openshift4/ose-machine-config-operator:v4.10.0-202303032215.p0.ga21b2b8.assembly.stream | RHSA-2023:1154 |
| Red Hat OpenShift Container Platform 4.10 | openshift4/ose-kubernetes-nmstate-handler-rhel8:v4.10.0-202303162241.p0.g68b1665.assembly.stream | RHSA-2023:1393 |
| Red Hat OpenShift Container Platform 4.11 | openshift4/ose-cluster-baremetal-operator-rhel8:v4.11.0-202301191245.p0.g4ffdd2f.assembly.stream | RHSA-2023:0565 |
| Red Hat OpenShift Container Platform 4.11 | openshift4/ose-machine-config-operator:v4.11.0-202302071115.p0.gc101063.assembly.stream | RHSA-2023:0651 |
| Red Hat OpenShift Container Platform 4.11 | openshift4/ose-installer:v4.11.0-202302130454.p0.g59d1196.assembly.stream | RHSA-2023:0774 |
Frequently Asked Questions
Is CVE-2021-4238 in your dependencies?
Find it across Go, including transitive dependencies.