Telstra outage traced to software fault in network time synchronization

Telstra's mobile network experienced a nationwide outage after a software fault disrupted time synchronization across several nodes around 4:30 a.m. Wednesday. The company attributed the disruption to a glitch that reset the GPS timer used for network timing. Services were largely restored later that day, and Telstra ruled out any cyber-attack.

Prior warnings from agencies and researchers Federal government agencies and academic researchers had previously identified the risk of single-point timing failures in telecommunications networks. In 2024, Australia's Cyber and Infrastructure Security Centre issued a public alert on critical infrastructure dependence on positioning, navigation, and timing systems.

An October 2025 alert from the same centre highlighted the reliance of critical communications assets on satellite-based timing and reminded operators of legal obligations to maintain backups. The federal government later introduced a requirement for telecommunications providers to maintain risk-management programs covering such hazards.

Swinburne University professor Allison Kealy told the ABC she had raised the scenario with Telstra earlier this year while seeking support for a proposed critical-infrastructure resilience research centre. She said the goal was to identify shared points of failure before an outage occurred.

Expert views on resilience Professor Kealy said a single software fault affecting a large portion of the network raised questions about whether primary and backup timing systems shared a common point of failure. She compared the situation to household clocks that remain independent until a shared power source is lost.