CVE-2026-43020

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.

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CVSS v3.1 Score

7.8

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0001

Probability of exploitation

0.03%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-787 Out-of-bounds Write

Affected Products

Vendor	Product	Versions
linux	linux_kernel	3.4 — 5.10.253
linux	linux_kernel	5.11 — 5.15.203
linux	linux_kernel	5.16 — 6.1.168
linux	linux_kernel	6.2 — 6.6.134
linux	linux_kernel	6.7 — 6.12.81
linux	linux_kernel	6.13 — 6.18.22
linux	linux_kernel	6.19 — 6.19.12
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All

References

Advisories & Patches

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

Frequently Asked Questions

What is CVE-2026-43020? +

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. It has a CVSS v3.1 base score of 7.8 (HIGH).

How severe is CVE-2026-43020? +

CVE-2026-43020 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0001, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-43020? +

CVE-2026-43020 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-43020? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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