Raw vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2026-43018 is a high-severity Use After Free (CWE-416) vulnerability in Linux Linux Kernel. Its CVSS base score is 8.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 18th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-8 (Security and Privacy Engineering Principles) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-43018 is a Use-After-Free (UAF) vulnerability in the Linux kernel's Bluetooth subsystem, specifically within the hci_le_remote_conn_param_req_evt function. The issue arises because hci_conn lookup and field access are not properly protected by the hdev lock, allowing the connection structure to be freed concurrently while still in use. This affects Linux kernel versions prior to the application of the referenced stable patches.
An attacker with adjacent network access (AV:A), such as within Bluetooth range, can exploit this with low complexity (AC:L) and no privileges or user interaction required (PR:N/UI:N). Successful exploitation could result in high impacts to confidentiality, integrity, and availability (C:H/I:H/A:H), with an overall CVSS v3.1 score of 8.8, potentially enabling remote code execution, data leakage, or system crashes on affected systems.
Mitigation involves applying the upstream kernel patches from the provided stable branch commits, which extend the hci_dev_lock critical section to fully cover all hci_conn usage and prevent the UAF. The fixes are available at: https://git.kernel.org/stable/c/1d0bdbfe3e91c11f0a704c52443a9446a10d699c, https://git.kernel.org/stable/c/59eecf0ffde15670e6a5e10c47be67f73d843b20, https://git.kernel.org/stable/c/5fb69e1eeea9d6cba80517e9f058b56b34bc3a81, https://git.kernel.org/stable/c/7cadb03be37e761130edb153544fe0770a842b19, and https://git.kernel.org/stable/c/b255531b27da336571411248c2a72a350662bd09. Security practitioners should prioritize updating Bluetooth-enabled Linux systems, especially those in environments with physical proximity risks.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-26617
Vulnerability Data
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_event: fix potential UAF in hci_le_remote_conn_param_req_evt hci_conn lookup and field access must be covered by hdev lock in hci_le_remote_conn_param_req_evt, otherwise it's possible it is freed concurrently. Extend the hci_dev_lock…
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critical section to cover all conn usage.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 3 hardening rules · 3 OS baselines
V1.4.3
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation can discover use-after-free bugs through dynamic analysis or fuzzing.
Engineering principles can require memory-safe constructs or languages that structurally avoid introducing use-after-free.
Process isolation confines the blast radius of use-after-free memory corruption to a single execution domain.
Memory protection controls limit exploitation impact by blocking unauthorized code execution from dangling pointers.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Vulnerability identification processes can discover use-after-free issues via scanning or analysis but do not prevent their introduction.
Routine patching removes known use-after-free instances after they have been introduced in released software.
Secure SDLC practices directly incorporate memory-safety tooling and reviews that prevent most use-after-free defects.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Secure SDLC mandates memory-safety practices that reduce use-after-free defects.
Application security requirements can specify memory-management rules that mitigate use-after-free.
Secure architecture principles include memory-safety design choices that limit use-after-free exposure.
Secure coding standards directly prescribe avoidance of use-after-free patterns.
Security testing in development can detect use-after-free bugs before release.
Change-management processes help ensure memory-safety fixes are deployed consistently.
Hardening callouts derived
Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (higher-evidence rows only; rows rated `none` are excluded).
Oracle Linux 8 (1 rule)
- V-248592 OL 8 must clear memory when it is freed to prevent use-after-free attacks. prevents CWE-416
RHEL 8 (1 rule)
- V-230279 RHEL 8 must clear memory when it is freed to prevent use-after-free attacks. prevents CWE-416
RHEL 9 (1 rule)
- V-257794 RHEL 9 must clear memory when it is freed to prevent use-after-free attacks. prevents CWE-416