CVE-2024-21803VulnerabilityPublished 30 Jan 2024Updated 29 May 2025

CVE-2024-21803: Linux kernel · Use After Free

Affects Linux kernelSource CVE Database V5

Not known to be exploited · CVSS 3.5 Low.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

3.5Low

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.4% chance of exploitation in 30 days – higher than 42% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Network
Attack Complexity: High
Privileges Required: Low
User Interaction: None
Scope: Changed
Confidentiality: None
Integrity: None
Availability: Low

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 30 Jan 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Linux Linux kernel	Affected =2.6.12-rc2	Fixed in–

AI-suggested

European organizations should prioritize the following mitigations: 1) Identify and inventory all Linux systems running kernel versions from v2.6.12-rc2 up to v6.8-rc1, focusing on those with Bluetooth enabled. 2) Apply kernel updates or patches as soon as they become available from trusted Linux distributions or kernel maintainers. If official patches are not yet released, consider disabling Bluetooth modules on critical systems where feasible to reduce the attack surface. 3) Implement strict access controls to limit local user privileges, minimizing the risk of exploitation by low-privileged users. 4) Monitor system logs and kernel messages for unusual Bluetooth-related errors or crashes that could indicate attempted exploitation. 5) For embedded and IoT devices, coordinate with vendors to ensure timely firmware updates or mitigations. 6) Employ host-based intrusion detection systems (HIDS) that can detect anomalous kernel behavior or memory corruption attempts. 7) Educate system administrators and security teams about this vulnerability to ensure rapid response and patch management.

Description

Use After Free vulnerability in Linux Linux kernel kernel on Linux, x86, ARM (bluetooth modules) allows Local Execution of Code. This vulnerability is associated with program files https://gitee.Com/anolis/cloud-kernel/blob/devel-5.10/net/bluetooth/af_bluetooth.C. This issue affects Linux kernel: from v2.6.12-rc2 before v6.8-rc1.

Impact

For European organizations, the impact of CVE-2024-21803 is primarily related to system stability and availability. Organizations relying on Linux systems with Bluetooth enabled—such as enterprise desktops, laptops, and IoT devices—could experience kernel crashes leading to denial of service conditions. While the vulnerability does not directly compromise confidentiality or integrity, disruption of critical systems could affect business operations, especially in sectors with high availability requirements like finance, healthcare, and telecommunications. The local nature of the exploit limits remote attacks, but insider threats or compromised user accounts could leverage this vulnerability to disrupt services. Additionally, embedded Linux devices used in industrial control systems or smart infrastructure across Europe might be affected if they run vulnerable kernel versions with Bluetooth enabled. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially as attackers may develop exploits over time.

Summary

CVE-2024-21803 is a Use After Free (UAF) vulnerability identified in the Linux kernel, specifically affecting the Bluetooth modules within the kernel source file af_bluetooth.c. This vulnerability impacts Linux kernel versions starting from v2.6.12-rc2 up to but not including v6.8-rc1. The flaw arises when the kernel improperly manages memory, leading to a scenario where a previously freed memory region is accessed again. Such a condition can cause undefined behavior, including potential kernel crashes or, in some cases, local code execution. The vulnerability is local, meaning an attacker must have some level of access to the system to exploit it. The CVSS v3.1 base score is 3.5, indicating a low severity primarily due to the high attack complexity and the requirement for low privileges but no user interaction. The impact vector is network (AV:N), but the attack complexity is high (AC:H), and privileges required are low (PR:L). The vulnerability affects confidentiality and integrity minimally but can impact availability by causing denial of service through kernel crashes. No known exploits are currently reported in the wild, and no patches have been linked yet. The vulnerability is rooted in the Bluetooth subsystem, which is commonly enabled on many Linux systems, including servers, desktops, and embedded devices. Given the wide deployment of the Linux kernel across architectures such as x86 and ARM, this vulnerability has a broad potential impact surface. However, exploitation is constrained by the need for local access and the complexity of triggering the flaw reliably.

CWE-416Use After Free (opens in a new tab)
Variant weaknessLikelihood of exploit: HighCWE Top 25 (2025): #7
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
Architecture and Design · Language Selection
Choose a language that provides automatic memory management.
Implementation · Attack Surface Reduction
When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

bugzilla.openanolis.cn/show_bug.cgi?id=8081 (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 8 Jul 2025, 01:40 UTC

WeaknessesCWE-416

Technical details

References

Community reviews

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