CVE-2026-68555 coturn: Chained mobility resumes allow authenticated remote memory exhaustion
An authenticated attacker can exhaust server memory by repeatedly resuming allocations when mobility is enabled, causing denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-68555?
CVE-2026-68555 is a medium-severity denial of service vulnerability in coturn, published on 19 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Coturn is a free open source implementation of TURN and STUN Server. In 4.15.0, an authenticated TURN user can repeatedly resume one allocation from fresh UDP 5-tuples without completing a handoff when the server enables --mobility. mobile_begin_transition() in src/server/ns_turn_server.c disarms each new session's allocation timeout and overwrites the allocation's single mobile_pending_resume link, leaving earlier pending sessions unreachable by the cleanup path, while copy_auth_parameters() ignores inc_quota() failure. The attacker can therefore retain unbounded server-side sessions and exhaust process memory even when --user-quota=1 is configured. This issue is fixed in version 4.16.0.
Weakness: CWE-400
Which versions are affected by CVE-2026-68555?
How do I fix CVE-2026-68555?
Upgrade to a fixed version.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-68555 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-68555 exists.
Sources
Also known as DEBIAN-CVE-2026-68555, GHSA-hpq3-g7x4-h7xx, MINI-rxrh-75f6-vpjh, UBUNTU-CVE-2026-68555.