Blutooth BR/EDR specification does not specify sufficient encryption key length and allows an attacker to influence key length negotiation

Description

The Bluetooth BR/EDR specification up to and including version 5.1 permits sufficiently low encryption key length and does not prevent an attacker from influencing the key length negotiation. This allows practical brute-force attacks (aka "KNOB") that can decrypt traffic and inject arbitrary ciphertext without the victim noticing.

Scores

EPSS (exploitation in 30 days)

2.7% · top 14% of all CVEs (4 Nov 2026)

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.6.

Weakness

• CWE-310 Cryptographic Issues (opens in a new tab)All about CWE-310 and its CVEs
• CWE-327 (opens in a new tab)All about CWE-327 and its CVEs

Affected products

• Bluetooth · BR/EDR

  • affected 5.1 – ≤ 5.1

What to do

Workaround: Bluetooth SIG Expedited Errata Correction 11838

References (30)

• VU#918987 (opens in a new tab)third-party-advisoryx_refsource_CERT-VNx_transferred
• http://www.cs.ox.ac.uk/publications/publication12404-abstract.html (opens in a new tab)x_refsource_MISCx_transferred
• https://www.usenix.org/conference/usenixsecurity19/presentation/antonioli (opens in a new tab)x_refsource_MISCx_transferred
• https://www.bluetooth.com/security/statement-key-negotiation-of-bluetooth/ (opens in a new tab)x_refsource_CONFIRMx_transferred
• 20190816 APPLE-SA-2019-8-13-3 Additional information for APPLE-SA-2019-7-22-4 watchOS 5.3 (opens in a new tab)mailing-listx_refsource_FULLDISCx_transferred
• 20190816 APPLE-SA-2019-8-13-1 Additional information for APPLE-SA-2019-7-22-2 macOS Mojave 10.14.6, Security Update 2019-004 High Sierra, Security Update 2019-004 Sierra (opens in a new tab)mailing-listx_refsource_FULLDISCx_transferred
• 20190816 APPLE-SA-2019-8-13-2 Additional information for APPLE-SA-2019-7-22-1 iOS 12.4 (opens in a new tab)mailing-listx_refsource_FULLDISCx_transferred
• 20190816 APPLE-SA-2019-8-13-4 Additional information for APPLE-SA-2019-7-22-5 tvOS 12.4 (opens in a new tab)mailing-listx_refsource_FULLDISCx_transferred
• http://www.huawei.com/en/psirt/security-advisories/huawei-sa-20190828-01-knob-en (opens in a new tab)x_refsource_CONFIRMx_transferred
• USN-4115-1 (opens in a new tab)vendor-advisoryx_refsource_UBUNTUx_transferred
• USN-4118-1 (opens in a new tab)vendor-advisoryx_refsource_UBUNTUx_transferred
• [debian-lts-announce] 20190914 [SECURITY] [DLA 1919-1] linux-4.9 security update (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [debian-lts-announce] 20190915 [SECURITY] [DLA 1919-2] linux-4.9 security update (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [debian-lts-announce] 20190925 [SECURITY] [DLA 1930-1] linux security update (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• USN-4147-1 (opens in a new tab)vendor-advisoryx_refsource_UBUNTUx_transferred
• RHSA-2019:2975 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
• openSUSE-SU-2019:2307 (opens in a new tab)vendor-advisoryx_refsource_SUSEx_transferred
• openSUSE-SU-2019:2308 (opens in a new tab)vendor-advisoryx_refsource_SUSEx_transferred
• RHSA-2019:3076 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
• RHSA-2019:3055 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
• RHSA-2019:3089 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
• RHSA-2019:3187 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
• RHSA-2019:3165 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
• RHSA-2019:3217 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
• RHSA-2019:3220 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
• RHSA-2019:3231 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
• RHSA-2019:3218 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
• RHSA-2019:3309 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
• RHSA-2019:3517 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
• RHSA-2020:0204 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2019-9506](https://trackcve.app/badge/CVE-2019-9506.svg)](https://trackcve.app/cve/CVE-2019-9506)

Record last updated 16 Sept 2024, 19:14 UTC.