What’s Vulnerable › Vulnerabilities

CVE-2026-43020: Bluetooth: MGMT: validate LTK enc_size on load

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-05-01 · updated 2026-06-17
• Weakness: CWE-787

Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: MGMT: validate LTK enc_size on load Load Long Term Keys stores the user-provided enc_size and later uses it to size fixed-size stack operations when replying to LE LTK requests. An enc_size larger than the 16-byte key buffer can therefore overflow the reply stack buffer. Reject oversized enc_size values while validating the management LTK record so invalid keys never reach the stored key state.

Affected products

• Linux kernel: from 3.4 before 5.10.253; from 5.11 before 5.15.203; from 5.16 before 6.1.168; from 6.2 before 6.6.134; from 6.7 before 6.12.81; from 6.13 before 6.18.22 — fixed in 5.10.253, 5.15.203, 6.1.168, 6.12.81, 6.18.22, 6.19.12

How to fix

Upgrade to a fixed version: Linux kernel 5.10.253, 5.15.203, 6.1.168, 6.12.81. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/0f37d1e65c6d71ad94ccfb5c602163c525db789d
• https://git.kernel.org/stable/c/257cdb960d8ff6d60bb6461b03c814b6cf0c9e64
• https://git.kernel.org/stable/c/40ba329e8b4cd2fb11b0caf5e6a543ceaebb6009
• https://git.kernel.org/stable/c/50fb64defa72a3fecd0af1ca7c6b47b5c5c2b257
• https://git.kernel.org/stable/c/82f342b3b006ca1d65f4890c05f2ec32fcb808b6
• https://git.kernel.org/stable/c/b8dbe9648d69059cfe3a28917bfbf7e61efd7f15
• https://git.kernel.org/stable/c/c34577f517b556fb6ca173d45bf7e766ae2564ce
• https://git.kernel.org/stable/c/f71695e81f4cb428f3c7e2138eae88199005b52c

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