Signal bug could let someone keep listening after you hang up
Vulnerability: Signal's calling flaw (CVE-2026-113380) lets attackers eavesdrop post-call termination due to improper shutdown handling.
Deep Analysis and Expert Commentary
The vulnerability exploits Signal's call termination logic, specifically when the internal event queue is flooded, preventing proper disconnection. This creates a window where audio (and potentially video) streams remain active despite the user ending the call. The attack path requires active participation in the call, limiting exploitation to malicious callers rather than passive eavesdroppers. Impact is significant for sensitive conversations, as post-call ambient audio could be captured. Mitigation involves updating to RingRTC 2.72.0 or later, though Signal's patch rollout varies by platform. Organizations relying on Signal for secure communications should verify endpoint updates and consider temporary call confirmation protocols.
Action Items
- Update Signal to the latest version on all devices immediately.
- Verify RingRTC library version (≥2.72.0) in enterprise deployments using Signal.
- Consider visual call termination confirmation for sensitive conversations until patches are confirmed.
Original Article Brief Intro
Malwarebytes Labs · 2026-10-21 · Vulnerability: Signal's calling flaw (CVE-2026-113380) lets attackers eavesdrop post-call termination due to improper shutdown handling.
Related Terms and Notes
CVE IDs
- CVE-2026-113380
Techniques / TTPs
- RingRTC — Open-source library providing voice/video calling components for Signal applications.
Context Notes
- call termination flaw
- CVSS 9.3 — Critical severity score indicating easy exploitability and high impact on confidentiality.
- Eavesdropping
- Privacy
- RingRTC
- Signal
- Signal vulnerability
- VoIP
- VoIP security