CVE-2023-3978 — net
MEDIUMCVE-2023-3978 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in golang.org/x/net. A fix is available for golang.org/x/net — see the affected versions and patch details below.
Improper rendering of text nodes in golang.org/x/net/html
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 CVE-2023-3978.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2023-3978 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,636 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
golang.org/x/netReal-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
Text nodes not in the HTML namespace are incorrectly literally rendered, causing text which should be escaped to not be. This could lead to an XSS attack.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | golang.org/x/net | all versions | 0.13.0go get golang.org/x/net@v0.13.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for golang.org/x/net, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update golang.org/x/net to 0.13.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-3978 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.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2023-3978 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-3978. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
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 |
|---|---|---|
| Cryostat 2 on RHEL 8 | cryostat-tech-preview/cryostat-rhel8-operator:2.3.1-11 | RHSA-2023:6031 |
| LVMS-4.14-RHEL-9 | lvms4/lvms-must-gather-rhel9:v4.14.1-3 | RHBA-2023:6863 |
| Migration Toolkit for Virtualization 2.4 | migration-toolkit-virtualization/mtv-rhel8-operator:2.4.3-3 | RHBA-2023:6109 |
| Red Hat Enterprise Linux 8 | container-tools:4.0-8090020230828093056.e7857ab1 | RHSA-2023:6938 |
| Red Hat Enterprise Linux 8 | container-tools:rhel8-8090020230825121312.e7857ab1 | RHSA-2023:6939 |
| Red Hat Enterprise Linux 9 | podman-2:4.6.1-5.el9 | RHSA-2023:6474 |
| Red Hat Migration Toolkit for Containers 1.7 | rhmtc/openshift-migration-controller-rhel8:v1.7.13-4 | RHSA-2023:5888 |
| Red Hat OpenShift Container Platform 4.12 | openshift4/ose-machine-api-operator:v4.12.0-202401190520.p0.g04504fb.assembly.stream | RHSA-2024:0485 |
Frequently Asked Questions
Is CVE-2023-3978 in your dependencies?
O3 Security finds CVE-2023-3978 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.