VulnerabilityPublished 2 Feb 2026Updated 30 Mar 2026

CVE-2026-20401: MediaTek chipset · Reachable Assertion

Affects MediaTek chipsetSource CVE Database V5

Not known to be exploited · CVSS 6.5 Medium.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score

6.5Medium

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

EPSS: 0.7% chance of exploitation in 30 days – higher than 53% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Adjacent
Attack Complexity: Low
Privileges Required: None
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: Adjacent: The vulnerable component is bound to the network stack, but the attack is limited at the protocol level to a logically adjacent topology. This can mean an attack must be launched from the same shared physical (e.g., Bluetooth or IEEE 802.11) or logical (e.g., local IP subnet) network, or from within a secure or otherwise limited administrative domain (e.g., MPLS, secure VPN to an administrative network zone).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
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 Feb 2026
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 26 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.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, 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 MT2735 – MT8797 18 affected builds	Fixed in–

AI-suggested

To mitigate CVE-2026-20401, organizations and users should promptly apply the official patch MOLY01738310 provided by MediaTek or device manufacturers. Network operators and security teams should monitor for rogue base stations or suspicious signaling activity indicative of man-in-the-middle attacks targeting mobile devices. Deploying base station authentication and detection mechanisms can reduce the risk of devices connecting to malicious infrastructure. Device manufacturers should ensure firmware updates are delivered securely and efficiently to end users. For high-risk environments, consider network segmentation and restricting device connectivity to trusted networks. Security teams should also educate users about the risks of connecting to unknown or untrusted cellular networks, although user interaction is not required for exploitation. Continuous monitoring of device behavior and anomaly detection can help identify potential exploitation attempts.

Description

In Modem, there is a possible system crash due to an uncaught exception. This could lead to remote denial of service, if a UE has connected to a rogue base station controlled by the attacker, with no additional execution privileges needed. User interaction is not needed for exploitation. Patch ID: MOLY01738310; Issue ID: MSV-5933.

Impact

The primary impact of CVE-2026-20401 is a remote denial of service on devices using affected MediaTek chipsets. This can disrupt mobile device availability, potentially affecting communication, data access, and critical services relying on mobile connectivity. In environments where devices are used for essential operations—such as emergency services, industrial IoT, or enterprise mobile deployments—a DoS could lead to operational downtime and safety risks. The attack requires proximity or control over a rogue base station, which may limit large-scale exploitation but poses a significant threat in targeted attacks or hostile environments. The vulnerability does not allow privilege escalation or data compromise, limiting its impact to availability. However, the widespread use of MediaTek chipsets in consumer and industrial devices globally means a large attack surface. Organizations with mobile fleets, IoT deployments, or critical infrastructure using these chipsets may face service interruptions and reputational damage if exploited.

CWE-617Reachable Assertion (opens in a new tab)
Base weakness
The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.
Implementation
Make sensitive open/close operation non reachable by directly user-controlled data (e.g. open/close resources)
Implementation · Input Validation
Perform input validation on user data.
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 30 Mar 2026, 19:29 UTC

WeaknessesCWE-617

Technical details

References

Community reviews

Related threats