VulnerabilityPublished 2 Mar 2026Updated 30 Mar 2026

CVE-2026-20439: MediaTek chipset · Use After Free

Affects MediaTek chipsetSource CVE Database V5

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Not known to be exploited · CVSS 4.4 Medium.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score

4.4Medium

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

EPSS: 0.07% chance of exploitation in 30 days – higher than 0% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Local
Attack Complexity: Low
Privileges Required: High
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

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

Attack Vector: Local: The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or remotely (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., tricking a legitimate user into opening a malicious document).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: High: The attacker is authorized with (i.e., requires) privileges that provide significant (e.g., administrative) control over the vulnerable component that could affect component-wide settings and files.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
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: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 2 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 30 Oct 2026.

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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity 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
MediaTek, Inc.MediaTek chipset	Affected MT2718 – MT8793 5 affected builds	Fixed in–

AI-suggested

To mitigate CVE-2026-20439, organizations should prioritize applying the official patch identified by MediaTek (Patch ID: ALPS10431955) as soon as it becomes available. Until patches are deployed, it is critical to restrict access to system-level privileges to trusted personnel and processes, minimizing the risk of privilege escalation that could enable exploitation. Implement strict access controls and monitoring to detect and prevent unauthorized privilege escalations. Employ runtime protections such as memory safety checks and use-after-free detection tools where possible to identify anomalous behavior in the imgsys component. Regularly update device firmware and software to incorporate security fixes. For device manufacturers and integrators, conduct thorough testing of MediaTek chipset-based products to ensure stability and security post-patch. Additionally, maintain incident response plans that include procedures for addressing denial of service conditions caused by such vulnerabilities. Network segmentation and limiting local access to critical devices can further reduce exposure. Finally, monitor security advisories from MediaTek and related vendors for updates or new mitigation guidance.

Description

In imgsys, there is a possible system crash due to use after free. This could lead to local denial of service if a malicious actor has already obtained the System privilege. User interaction is not needed for exploitation. Patch ID: ALPS10431955; Issue ID: MSV-5826.

Impact

The primary impact of CVE-2026-20439 is a local denial of service caused by system crashes due to use-after-free in the imgsys component. While the vulnerability does not directly compromise confidentiality or integrity, the resulting system instability can disrupt device functionality, potentially affecting critical operations in embedded systems or mobile devices. Since exploitation requires system-level privileges, the risk is mitigated somewhat by the prerequisite of prior compromise or insider threat. However, in environments where attackers have already escalated privileges, this vulnerability can be leveraged to cause persistent denial of service, impacting availability and potentially leading to operational downtime. This can affect manufacturers, service providers, and end-users relying on MediaTek chipsets, especially in sectors where device reliability is critical. The absence of known exploits in the wild reduces immediate risk but does not eliminate the threat, especially as patches are not yet widely deployed. Organizations with large deployments of affected devices may face increased support and maintenance costs due to potential crashes and instability.

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

corp.mediatek.com/product-security-bulletin/March-2026 (opens in a new tab)

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 30 Mar 2026, 19:43 UTC

WeaknessesCWE-416

Technical details

References

Community reviews

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