What’s Vulnerable › Vulnerabilities

CVE-2025-40301: Bluetooth: hci_event: validate skb length for unknown CC opcode

• Severity: high (CVSS 7.6 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-12-08 · updated 2026-10-14

Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_event: validate skb length for unknown CC opcode In hci_cmd_complete_evt(), if the command complete event has an unknown opcode, we assume the first byte of the remaining skb->data contains the return status. However, parameter data has previously been pulled in hci_event_func(), which may leave the skb empty. If so, using skb->data[0] for the return status uses un-init memory. The fix is to check skb->len before using skb->data.

Affected products

• Linux kernel: 6.1 — fixed in 6.18

How to fix

Upgrade to a fixed version: Linux kernel 6.18. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/1a0ddaaf97405dbd11d4cb5a961a3f82400e8a50
• https://git.kernel.org/stable/c/5c5f1f64681cc889d9b13e4a61285e9e029d6ab5
• https://git.kernel.org/stable/c/779f83a91d4f1bf5ddfeaf528420cbb6dbf03fa8
• https://git.kernel.org/stable/c/cf2c2acec1cf456c3d11c11a7589e886a0f963a9
• https://git.kernel.org/stable/c/fea895de78d3bb2f0c09db9f10b18f8121b15759

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