CVE-2026-80761 Bluetooth: ISO: zero the sockaddr before returning it in getname
An unprivileged local attacker can leak uninitialized kernel stack memory via Bluetooth ISO socket calls, potentially exposing sensitive data.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-80761?
CVE-2026-80761 is a vulnerability in Linux, published on 4 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: ISO: zero the sockaddr before returning it in getname
iso_sock_getname() fills a struct sockaddr_iso in place and returns its size without clearing it first, so bytes it does not write are copied to user space from the kernel stack. The getsockname(2) and getpeername(2) paths both run through do_getsockname(), which hands getname() an uninitialized sockaddr_storage on the stack and copies back up to the number of bytes getname() returns, so the driver has to initialize every byte it accounts for.
Two ranges are left uninitialized:
- struct sockaddr_iso is 10 bytes but only 9 are written (family, iso_bdaddr, iso_bdaddr_type), leaking the trailing pad byte on every call.
- for a broadcast peer (BIS_LINK or PA_LINK) the returned length grows by sizeof(struct sockaddr_iso_bc), but only bc_sid, bc_num_bis and bc_bis are filled; bc_bdaddr and bc_bdaddr_type, the first 7 bytes of that structure, are never written.
An unprivileged process can open a BTPROTO_ISO socket and reach the pad leak with getsockname(); the broadcast leak needs an established BIS/PA connection. l2cap and rfcomm already memset their sockaddr in getname for the same reason; do the same here.
Which versions are affected by CVE-2026-80761?
How do I fix CVE-2026-80761?
Apply the vendor's patch.
Is CVE-2026-80761 being exploited?
There is no known exploitation of CVE-2026-80761 in the wild and no public exploit code.
Sources
Also known as AZL-99594, BELL-CVE-2026-80761, DEBIAN-CVE-2026-80761, GHSA-xhh3-4cvw-88vv, UBUNTU-CVE-2026-80761.