Science & Tech · Cybersecurity · 2 hrs ago
Signal fixes flaw that could keep calls active after hang-up
Signal fixed a critical flaw that could stop some calls from ending properly after a user hung up.
The issue affected RingRTC, the open-source library Signal uses to handle voice and video calls.
A caller could flood the call system’s event queue, delaying the hang-up request so it was not processed.
As a result, audio and possibly video could remain active while the person who hung up believed the call had ended.
The flaw was rated critical, with a CVSS score of 9.3, and a conceptual proof of concept was published; the sources do not say it has been exploited in real attacks.
Signal addressed the flaw in RingRTC version 2.72.0, released on September 4.
Users should update Signal and check the call indicator to make sure a call has ended.
Signal fixed a critical flaw that could leave audio or video active after a user believed a call had ended.
The vulnerability, CVE-2026-113380, affected Signal’s RingRTC calling library in versions before 2.72.0.
A remote caller could flood RingRTC’s event queue and prevent a hang-up request from being processed.
The flaw was rated 9.3 on the CVSS severity scale.
Signal users are advised to update their apps and check that calls have ended.
- Who
- Signal users and a remote caller who could exploit the flaw.
- What
- A flaw could prevent a call from ending properly, leaving audio and possibly video active.
- When
- The fixed RingRTC 2.72.0 was released on September 4, according to SecurityWeek; The Register says it was pushed out last month.
- Where
- Signal’s RingRTC library, used for voice and video calls.
- Why
- A caller could flood the call-management event queue, delaying or blocking the hang-up request.
This story does not have two clearly opposing sides.
SecurityWeek reports that RingRTC version 2.72.0, which fixes the flaw, was released.
Details of the flaw were published, and NIST added the CVE to the NVD database, according to SecurityWeek.
- Vulnerability
- CVE-2026-113380
- Severity
- CVSS score of 9.3
- Affected library
- RingRTC
- Fixed version
- 2.72.0
- Queue attack
- Flooding the FSM event queue could block a hang-up request
3 sources
What people are saying
Flood the queue with junk and the hang-up waits behind attacker noise forever, so the call (microphone, possibly camera) is never torn down,