CVE-2021-38561 — x/text
HIGHCVE-2021-38561 is a high-severity (CVSS 7.5) Out-of-bounds Read vulnerability in golang.org/x/text. A fix is available for golang.org/x/text — see the affected versions and patch details below.
golang.org/x/text/language Out-of-bounds Read vulnerability
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.
- 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-2021-38561.
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
golang.org/x/textReal-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
golang.org/x/text/language in golang.org/x/text before 0.3.7 can panic with an out-of-bounds read during BCP 47 language tag parsing. Index calculation is mishandled. If parsing untrusted user input, this can be used as a vector for a denial-of-service attack.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | golang.org/x/text | all versions | 0.3.7go get golang.org/x/text@v0.3.7 |
Affected Products
textgolangDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for golang.org/x/text, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update golang.org/x/text to 0.3.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-38561 is resolved across your whole dependency graph.
Workarounds
Stop feeding it untrusted input: reject or quarantine files and payloads from unverified sources until you can upgrade, restrict accepted formats to the ones you actually need, and run the parsing or decoding step in a least-privileged sandbox or short-lived worker so a crash or corrupted read cannot reach the rest of the process.
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.
This flaw may be triggered only by accepting untrusted user input to the vulnerable golang's library. The overall DoS attack vector depends directly on how the library's input is exposed by the consuming application, thus Red Hat rates impact as Moderate. In Red Hat Advanced Cluster Management for Kubernetes (RHACM)…
| Product | Fixed in | Advisory |
|---|---|---|
| Logging subsystem for Red Hat OpenShift 5.4 | openshift-logging/elasticsearch-rhel8-operator:v5.4.3-12 | RHSA-2022:5556 |
| OpenShift Developer Tools and Services for OCP 4.7 | ocp-tools-4/service-binding-operator-bundle:v1.1.1-4 | RHSA-2022:5525 |
| OpenShift Logging 5.2 | openshift-logging/elasticsearch-rhel8-operator:v5.2.13-1 | RHSA-2022:5909 |
| OpenShift Logging 5.3 | openshift-logging/elasticsearch-rhel8-operator:v5.3.10-1 | RHSA-2022:5908 |
| Red Hat OpenShift Container Platform 4.11 | cri-o-0:1.24.5-2.rhaos4.11.gitb007cb6.el8 | RHBA-2023:1649 |
| Red Hat OpenShift Container Platform 4.11 | openshift4/cloud-event-proxy-rhel8:v4.11.0-202208020706.p0.g642796d.assembly.stream | RHSA-2022:5070 |
| Red Hat OpenShift Container Platform 4.11 | openshift4/ose-sriov-network-operator:v4.11.0-202208301406.p0.gb4f9fbd.assembly.stream | RHSA-2022:6287 |
| Red Hat OpenShift Container Platform 4.11 | openshift4/kubernetes-nmstate-rhel8-operator:v4.11.0-202209130958.p0.g444141e.assembly.stream | RHSA-2022:6537 |
Frequently Asked Questions
Is CVE-2021-38561 in your dependencies?
Find it across Go, including transitive dependencies.