MTN Nigeria: SS7 interception and subscriber data exposure
An SS7 interception campaign targeting MTN Nigeria exposes SIM numbers for millions of subscribers. The implications for mobile fintech are immediate.
Severity
4Affected country
NGSector
Banking & fintechPublished
25 May 2026
Our score measures operational relevance to Africa — not the global virality of the story.
Contents · 5
Context
MTN Nigeria, the country's largest operator with 75 million subscribers, confirmed detecting SS7 vulnerability exploitation attempts targeting its signalling platform.
What happened
Between May 12 and 18, 2026, unidentified actors used compromised SS7 interconnection points to intercept authentication SMS messages sent to MTN Nigeria subscribers. The attack primarily targeted users of MoMo, MTN's mobile wallet.
African exposure
Nigeria alone accounts for 28% of MoMo transactions in sub-Saharan Africa. This compromise potentially affects the entire SMS authentication chain in the Nigerian fintech ecosystem.
What organisations should retain
- Migrate SMS authentication to TOTP or passkeys for all critical access.
- Request MTN Nigeria provide an SS7 log audit for the affected period.
- Reassess KYC policies that rely exclusively on SMS OTPs.
Conclusion
The SS7 attack against MTN Nigeria serves as a reminder that telecom infrastructure is a direct attack vector against African mobile finance. The fix is not technical — it is architectural.
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