CVE-2026-43020
CVE-2026-43020 is a high-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-787.
Key facts
- Severity: High (CVSS 3.x base score 7.8)
- EPSS exploit prediction: 0% (3rd percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-26619
- Weakness: CWE-787
- Affected product: Linux Linux Kernel
- Published:
- Last modified:
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.
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.
- How severe is CVE-2026-43020?
- CVE-2026-43020 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2026-43020 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (3rd percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-43020?
- CVE-2026-43020 primarily affects Linux Linux Kernel. In total, 7 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2026-43020?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- Does CVE-2026-43020 have an EU (EUVD) identifier?
- Yes. CVE-2026-43020 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-26619.
- When was CVE-2026-43020 published?
- CVE-2026-43020 was published on 2026-05-01 and last updated on 2026-06-17.
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
Affected products (7)
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:*
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