CVE-2026-74300 Bluetooth: hci: validate codec capability element length
A malformed Bluetooth controller response can cause an out-of-bounds read in the Linux kernel, potentially leading to memory corruption or system crashes.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-74300?
CVE-2026-74300 is a high-severity memory corruption vulnerability in Linux, published on 15 Aug 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: hci: validate codec capability element length
Read Local Codec Capabilities returns a sequence of capability elements. Each element starts with a one-byte length followed by that many payload bytes.
hci_read_codec_capabilities() checks that the skb contains the length byte, but then validates only caps->len against the remaining skb length. A malformed controller response with one remaining byte and caps->len set to one passes that check even though the element needs two bytes. The parser then records a two-byte capability and copies one byte beyond the advertised response payload into the codec list.
Validate the full element size, including the length byte, before adding it to the accumulated capability length. This preserves all well-formed capability elements and drops only truncated controller responses.
Which versions are affected by CVE-2026-74300?
How do I fix CVE-2026-74300?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-74300 being exploited?
There is no known exploitation of CVE-2026-74300 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-74300, DEBIAN-CVE-2026-74300, GHSA-8wcp-4xmv-gqvg, UBUNTU-CVE-2026-74300.