CyberSecBulletin
CVE-2026-20479NVD status: Analyzed

MediaTek chipset: Out-of-bounds Read

Published Updated By the CyberSecBulletin desk

CVE-2026-20479 is a high-severity out-of-bounds read vulnerability in MediaTek chipset from MediaTek, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected MediaTek chipset versions: MT2735; MT6833; MT6853, and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.71% chance of exploitation within 30 days, higher than 54% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Check which version of MediaTek chipset you run against the affected versions below, and install the vendor's latest release.
  2. Read the advisory on mediatek.com for workarounds and exact fixed builds.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
MediaTekMediaTek chipsetMT2735; MT6833; MT6853; MT6855; MT6873; MT6875; MT6877; MT6880; and 11 more rangesNot stated
MediaTekMt2735 FirmwareNot specified in the recordNot stated
MediaTekMt6833 FirmwareNot specified in the recordNot stated
MediaTekMt6853 FirmwareNot specified in the recordNot stated
MediaTekMt6855 FirmwareNot specified in the recordNot stated
MediaTekMt6873 FirmwareNot specified in the recordNot stated
MediaTekMt6875 FirmwareNot specified in the recordNot stated
MediaTekMt6877 FirmwareNot specified in the recordNot stated
MediaTekMt6880 FirmwareNot specified in the recordNot stated
MediaTekMt6883 FirmwareNot specified in the recordNot stated
MediaTekMt6885 FirmwareNot specified in the recordNot stated
MediaTekMt6889 FirmwareNot specified in the recordNot stated
MediaTekMt6890 FirmwareNot specified in the recordNot stated
MediaTekMt6891 FirmwareNot specified in the recordNot stated
MediaTekMt6893 FirmwareNot specified in the recordNot stated
MediaTekMt8675 FirmwareNot specified in the recordNot stated
MediaTekMt8771 FirmwareNot specified in the recordNot stated
MediaTekMt8791 FirmwareNot specified in the recordNot stated
MediaTekMt8791t FirmwareNot specified in the recordNot stated
MediaTekMt8797 FirmwareNot specified in the recordNot stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
NoneNo data is disclosed.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CISA (ADP).

Official description

In Modem, there is a possible out of bounds read due to a missing bounds check. 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: MOLY00741071; Issue ID: MSV-7620.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Out-of-bounds Read

The product reads data past the end, or before the beginning, of the intended buffer.

How developers prevent this class of flaw

  • Use a language that provides appropriate memory abstractions.

More Out-of-bounds Read vulnerabilities (CWE-125)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in MediaTek chipset

All MediaTek chipset vulnerabilities

Recent Out-of-bounds Read vulnerabilities

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