CyberSecBulletin
CVE-2023-20689NVD status: Modified

MT6739, MT8167, MT8321, MT8365, MT8385…: Integer Overflow or Wraparound

Published Updated By the CyberSecBulletin desk

CVE-2023-20689 is a high-severity integer overflow or wraparound vulnerability in MT6739, MT8167, MT8321, MT8365, MT8385, MT8666, MT8765, MT8788 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 MT6739, MT8167, MT8321, MT8365, MT8385, MT8666, MT8765, MT8788 versions: Android 11.0 / IOT-v23.0 (Yocto 4.0). The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.45% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Check which version of MT6739, MT8167, MT8321, MT8365, MT8385, MT8666, MT8765, MT8788 you run against the affected versions below, and install the vendor's latest release.
  2. Read the advisory on corp.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
MediaTekMT6739, MT8167, MT8321, MT8365, MT8385, MT8666, MT8765, MT8788Android 11.0 / IOT-v23.0 (Yocto 4.0)Not stated
Linux FoundationYocto4.0Not stated
GoogleAndroid11.0Not 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 NVD.

Official description

In wlan firmware, there is possible system crash due to an integer overflow. This could lead to remote denial of service with no additional execution privileges needed. User interaction is not needed for exploitation. Patch ID: ALPS07664741; Issue ID: ALPS07664741.

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

The underlying weakness: Integer Overflow or Wraparound

The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.

How developers prevent this class of flaw

  • Ensure that all protocols are strictly defined, such that all out-of-bounds behavior can be identified simply, and require strict conformance to the protocol.
  • Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. If possible, choose a language or compiler that performs automatic bounds checking.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Use libraries or frameworks that make it easier to handle numbers without unexpected consequences. Examples include safe integer handling packages such as SafeInt (C++) or IntegerLib (C or C++).

More Integer Overflow or Wraparound vulnerabilities (CWE-190)

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 MT6739, MT8167, MT8321, MT8365, MT8385, MT8666, MT8765, MT8788

All MT6739, MT8167, MT8321, MT8365, MT8385, MT8666, MT8765, MT8788 vulnerabilities

Recent Integer Overflow or Wraparound vulnerabilities

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