Telmex Service Outage Impacts Chihuahua and beyond

Chihuahua, Chih. – December 7, 2025

A widespread outage of Telmex landline and internet services affected a important portion of the state of Chihuahua and at least 18 other Mexican states on December 7, 2025. The disruption began in the early afternoon and continued for several hours, impacting residential and business customers alike.

Extent of the Outage

Reports indicate that the outage extended beyond Chihuahua to include states such as Sonora, Sinaloa, Durango, Coahuila, Nuevo León, and Mexico City[[Milenio]. Users reported complete loss of internet connectivity and inability to make or receive calls on Telmex landlines.The scale of the outage prompted numerous complaints on social media, with users expressing frustration over the lack of service and communication from Telmex.

Cause of the Disruption

Telmex initially attributed the outage to a technical failure in its network infrastructure.Later, the company confirmed that the disruption was caused by a cyberattack that affected its systems[[El Financiero]. The attack targeted core network components, leading to the widespread service interruption. Telmex stated that it promptly activated its security protocols and began working to restore service.

Restoration Efforts and Timeline

Telmex engineers worked throughout the night to identify and mitigate the effects of the cyberattack and restore service. The company reported that service was gradually being restored in affected areas starting late on December 7th and continuing into December 8th[[Telmex Press Release]. Full service restoration was expected by the end of December 8th, though some users may experience intermittent connectivity issues during the recovery period.

Security Measures and Future Prevention

Following the incident,Telmex announced plans to enhance its cybersecurity measures to prevent future attacks. These measures include strengthening network defenses, implementing advanced threat detection systems, and increasing security awareness training for employees. The company is also collaborating with cybersecurity experts and government agencies to investigate the attack and identify vulnerabilities in its infrastructure.

Key Takeaways

• A significant Telmex outage impacted Chihuahua and at least 18 other Mexican states.
• the outage was caused by a cyberattack targeting Telmex’s network infrastructure.
• Telmex is working to restore service and has announced plans to enhance its cybersecurity measures.
• The incident highlights the growing threat of cyberattacks on critical infrastructure.

This outage serves as a stark reminder of the vulnerability of telecommunications networks to cyberattacks. As reliance on internet and phone services continues to grow, robust cybersecurity measures are essential to ensure the continuity of these critical services. Telmex’s response and subsequent security enhancements will be closely watched by the industry as a case study in managing and mitigating the impact of such incidents.