CVE-2026-31512 Bluetooth: L2CAP: Validate PDU length before reading SDU length in l2cap_ecred_data_rcv()
A missing length check in the Linux kernel Bluetooth L2CAP handler allows remote attackers to cause a denial of service via malformed packets.
- 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-2026-31512?
CVE-2026-31512 is a medium-severity denial of service vulnerability in Linux kernel, published on 22 Apr 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: L2CAP: Validate PDU length before reading SDU length in l2cap_ecred_data_rcv()
l2cap_ecred_data_rcv() reads the SDU length field from skb->data using get_unaligned_le16() without first verifying that skb contains at least L2CAP_SDULEN_SIZE (2) bytes. When skb->len is less than 2, this reads past the valid data in the skb.
The ERTM reassembly path correctly calls pskb_may_pull() before reading the SDU length (l2cap_reassemble_sdu, L2CAP_SAR_START case). Apply the same validation to the Enhanced Credit Based Flow Control data path.
Which versions are affected by CVE-2026-31512?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-31512?
Apply the vendor's patch.
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-2026-31512 being exploited?
There is no known exploitation of CVE-2026-31512 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-31512, DEBIAN-CVE-2026-31512, GHSA-r6qv-6h22-hpj4, ROOT-OS-DEBIAN-11-CVE-2026-31512, ROOT-OS-DEBIAN-12-CVE-2026-31512, ROOT-OS-DEBIAN-13-CVE-2026-31512 and 3 more.