Researchers Find 84 Flaws in the Guts of 4G and 5G Networks
A Singapore university team says weaknesses in mobile core software could let attackers knock users offline or hijack their sessions.
Key points
- Researchers at Nanyang Technological University in Singapore disclosed 84 vulnerabilities affecting 4G and 5G core networks.
- The flaws could allow denial-of-service attacks, knocking the network offline for users.
- One flaw could enable session hijacking, letting an attacker take over a user's live connection.
- The bugs sit in the core software that carriers run, not in handsets or SIM cards.
- No active exploitation has been reported.
A team of academic researchers has uncovered 84 security flaws in the software that runs modern mobile networks, weaknesses that could let attackers cut users off or, in the worst case, hijack their live phone sessions.
The research comes from Nanyang Technological University in Singapore, first reported by The Hacker News.
The flaws sit inside what the industry calls the "core network": the back-end computers a carrier operates to route calls and mobile data. Your phone talks to a cell tower; the tower talks to the core. If the core misbehaves, so does everything on top of it.
What can attackers actually do with these bugs?
Two things. They can trigger a denial-of-service, which floods or crashes a system so real users can't get through. Or they can hijack a user's session, seizing the live link between a phone and the network as if they were the legitimate owner.
A denial-of-service against a mobile core isn't a minor inconvenience. Emergency calls, payment terminals and hospital devices all ride the same infrastructure.
Session hijacking is the more alarming scenario. An attacker who seizes a session could intercept traffic tied to that account or impersonate the subscriber on the network.
Who is at risk?
Mobile carriers, not consumers directly. The vulnerabilities live in equipment that network providers operate, and ordinary customers can't patch a mobile core from their handset.
If a carrier's core is attacked, though, customers feel it: dropped service, failed calls, or exposure of their traffic in a hijack scenario.
| Detail | Figure |
|---|---|
| Vulnerabilities disclosed | 84 |
| Networks affected | 4G and 5G cores |
| Research team | Nanyang Technological University, Singapore |
| Main risks | Denial-of-service, session hijacking |
| Known exploitation | None reported |
How were the flaws found?
The Singapore team studied the protocols and software carriers use to run their cores, then probed for weaknesses triggerable from within the network. The problems are described as a "widespread class" of issues, meaning the same underlying design mistakes appear across multiple products from multiple vendors.
That framing matters. It's not one buggy box from one supplier; it's a pattern, and that makes patching harder to coordinate and easier to miss.
Is this being exploited right now?
No public evidence of exploitation has surfaced. The disclosure is a research finding, not an incident report. Vendors and carriers now have to confirm which of their products are affected and issue fixes.
History says patching mobile core equipment is slow. Carriers test heavily before touching production systems, because a bad update can drop service for millions of subscribers. The denial-of-service pattern here echoes what we reported on 30 July, when a flaw in an industrial protocol left dozens of Mitsubishi products exposed with no fix shipped.
What should ordinary customers do?
Nothing on your phone will fix this. There's no app update, no setting to toggle. Responsibility sits with carriers and equipment vendors.
If your mobile service drops in a way that feels unusual, report it to your provider, but an everyday outage is still far the more likely cause. Watch for advisories from your carrier over the coming weeks.
For security teams at telecoms, the practical work starts now: inventory core components and prioritise segments handling authentication and session management.
