Linux Kernel up to 6.19.11 Bluetooth enc_size stack-based overflow

CVSS Meta Temp Score
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CTI Interest Score
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7.6$0-$5k0.00

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.19.11 and classified as critical. This impacts an unknown function of the component Bluetooth. Such manipulation of the argument enc_size leads to stack-based overflow. This vulnerability is traded as CVE-2026-43020. There is no exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.19.11 and classified as critical. Affected by this issue is an unknown code of the component Bluetooth. The manipulation of the argument enc_size with an unknown input leads to a stack-based overflow vulnerability. Using CWE to declare the problem leads to CWE-121. A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function). Impacted is confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at git.kernel.org. This vulnerability is handled as CVE-2026-43020 since 05/01/2026. The exploitation is known to be easy. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 05/31/2026).

The vulnerability scanner Nessus provides a plugin with the ID 318033 (RockyLinux 9 : kernel (RLSA-2026:21556)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 5.10.253, 5.15.203, 6.1.168, 6.6.134, 6.12.81, 6.18.22 or 6.19.12 eliminates this vulnerability. Applying the patch 0f37d1e65c6d71ad94ccfb5c602163c525db789d/257cdb960d8ff6d60bb6461b03c814b6cf0c9e64/c34577f517b556fb6ca173d45bf7e766ae2564ce/f71695e81f4cb428f3c7e2138eae88199005b52c/82f342b3b006ca1d65f4890c05f2ec32fcb808b6/50fb64defa72a3fecd0af1ca7c6b47b5c5c2b257/40ba329e8b4cd2fb11b0caf5e6a543ceaebb6009/b8dbe9648d69059cfe3a28917bfbf7e61efd7f15 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (318033). Once again VulDB remains the best source for vulnerability data.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.0
VulDB Meta Temp Score: 7.6

VulDB Base Score: 8.0
VulDB Temp Score: 7.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Stack-based overflow
CWE: CWE-121 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 318033
Nessus Name: RockyLinux 9 : kernel (RLSA-2026:21556)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 5.10.253/5.15.203/6.1.168/6.6.134/6.12.81/6.18.22/6.19.12
Patch: 0f37d1e65c6d71ad94ccfb5c602163c525db789d/257cdb960d8ff6d60bb6461b03c814b6cf0c9e64/c34577f517b556fb6ca173d45bf7e766ae2564ce/f71695e81f4cb428f3c7e2138eae88199005b52c/82f342b3b006ca1d65f4890c05f2ec32fcb808b6/50fb64defa72a3fecd0af1ca7c6b47b5c5c2b257/40ba329e8b4cd2fb11b0caf5e6a543ceaebb6009/b8dbe9648d69059cfe3a28917bfbf7e61efd7f15

Timelineinfo

05/01/2026 Advisory disclosed
05/01/2026 +0 days CVE reserved
05/01/2026 +0 days VulDB entry created
05/31/2026 +30 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-43020 (🔒)
GCVE (CVE): GCVE-0-2026-43020
GCVE (VulDB): GCVE-100-360644

Entryinfo

Created: 05/01/2026 17:43
Updated: 05/31/2026 08:30
Changes: 05/01/2026 17:43 (59), 05/31/2026 08:30 (2)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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