What’s Vulnerable › Vulnerabilities

CVE-2026-98457: Bluetooth: L2CAP: validate frame length before control and FCS access

• Severity: unknown
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-18 · updated 2026-10-19

Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: validate frame length before control and FCS access l2cap_data_rcv() unpacks either a two-byte or four-byte control field without first ensuring that it is present. A short ERTM or streaming-mode frame can therefore cause an out-of-bounds read. There is a second short-frame case when CRC16 is enabled. After the control field is pulled, l2cap_check_fcs() subtracts two from skb->len without checking it. If fewer than two bytes remain, the subtraction wraps; skb_trim() leaves the buffer unchanged and the subsequent FCS load reads past the logical end of the frame. Validate that the frame contains both its control field and, when enabled, its FCS before either field is accessed.

Affected products

• Linux kernel: 2.6.32 — fixed in 7.3

How to fix

Upgrade to a fixed version: Linux kernel 7.3. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/1fdbb2a712a9a162ee817c959740face80b3d929
• https://git.kernel.org/stable/c/3acf6a0038ec0d4e8f4dcbfc2a557dff5f61cb70
• https://git.kernel.org/stable/c/4373ba79a267947e771c438507f7b103e30bdb21
• https://git.kernel.org/stable/c/6c78a213d9070b610c7f418af2c25b66180b7e37
• https://git.kernel.org/stable/c/8c7556c7cd17e073bbefdc4a9a4694a207544c37
• https://git.kernel.org/stable/c/965bd88ed4b4763cb765dd65885adcfa588c6b14
• https://git.kernel.org/stable/c/c6a288e6001bcce16553c3853e0f5a45eaaf85c7
• https://git.kernel.org/stable/c/f557274af7b94b6134692e6f26b880f1e34c15bf

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