CVE-2026-33063 — ausf
Fix: free5gc/ausf@3b9ac44CVE-2026-33063 is a NULL Pointer Dereference vulnerability in github.com/free5gc/ausf. A fix is available for github.com/free5gc/ausf — see the affected versions and patch details below.
free5GC AUSF UE Authentication Panic on Nil SuciSupiMap Interface Conversion
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-2026-33063.
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.
Real-World Exposure
github.com/free5gc/ausfReal-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
free5GC is an open source 5G core network. free5GC AUSF prior to version 1.4.2 has is an Improper Null Check vulnerability leading to Denial of Service. All deployments of free5GC v4.0.1 using the AUSF UE authentication service (/nausf-auth/v1/ue-authentications endpoint) are affected. A remote attacker can cause the AUSF service to panic and crash by sending a crafted UE authentication request that triggers a nil interface conversion in the GetSupiFromSuciSupiMap function. This results in complete denial of service for the AUSF authentication service. The GetSupiFromSuciSupiMap function attempts to perform an interface conversion from interface{} to *context.SuciSupiMap without checking if the underlying value is nil. When SuciSupiMap is nil, the code panics with "interface conversion: interface {} is nil, not *context.SuciSupiMap". free5GC AUSF version 1.4.2 patches the issue. There is no direct workaround at the application level. The recommendation is to apply the provided patch or restrict access to the AUSF API to trusted sources only.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/free5gc/ausf | all versions | 1.4.2go get github.com/free5gc/ausf@v1.4.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/free5gc/ausf, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/free5gc/ausf to 1.4.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-33063 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-2026-33063 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-33063. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-33063 in your dependencies?
O3 Security finds CVE-2026-33063 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.