CyberSecBulletin
CVE-2022-20110NVD status: Modified

MT6580, MT6735, MT6737, MT6739, MT6750…: Time-of-check Time-of-use (TOCTOU) Race Condition

Published Updated By the CyberSecBulletin desk

CVE-2022-20110 is a high-severity time-of-check time-of-use (TOCTOU) race condition vulnerability in MT6580, MT6735, MT6737, MT6739, MT6750, MT6750S, MT6753, MT6757, MT6757C, MT6757CD, MT6757CH, MT6761, MT6762, MT6763, MT6765, MT6768, MT6769, MT6771, MT6779, MT6781, MT6785, MT6797, MT6833, MT6853, MT6853T, MT6873, MT6875, MT6877, MT6883, MT6885, MT6889, MT6893, MT8167, MT8168, MT8173, MT8185, MT8321, MT8362A, MT8365, MT8385, MT8666, MT8675, MT8695, MT8696, MT8765, MT8766, MT8768, MT8786, MT8788, MT8789, MT8791, MT8797 from MediaTek, with a CVSS 3.1 base score of 7.0 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. Affected MT6580, MT6735, MT6737, MT6739, MT6750, MT6750S, MT6753, MT6757, MT6757C, MT6757CD, MT6757CH, MT6761, MT6762, MT6763, MT6765, MT6768, MT6769, MT6771, MT6779, MT6781, MT6785, MT6797, MT6833, MT6853, MT6853T, MT6873, MT6875, MT6877, MT6883, MT6885, MT6889, MT6893, MT8167, MT8168, MT8173, MT8185, MT8321, MT8362A, MT8365, MT8385, MT8666, MT8675, MT8695, MT8696, MT8765, MT8766, MT8768, MT8786, MT8788, MT8789, MT8791, MT8797 versions: Android 9.0, 10.0, 11.0, 12.0. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.08% 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 MT6580, MT6735, MT6737, MT6739, MT6750, MT6750S, MT6753, MT6757, MT6757C, MT6757CD, MT6757CH, MT6761, MT6762, MT6763, MT6765, MT6768, MT6769, MT6771, MT6779, MT6781, MT6785, MT6797, MT6833, MT6853, MT6853T, MT6873, MT6875, MT6877, MT6883, MT6885, MT6889, MT6893, MT8167, MT8168, MT8173, MT8185, MT8321, MT8362A, MT8365, MT8385, MT8666, MT8675, MT8695, MT8696, MT8765, MT8766, MT8768, MT8786, MT8788, MT8789, MT8791, MT8797 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.

Affected products and versions

VendorProductAffected versionsFixed in
MediaTekMT6580, MT6735, MT6737, MT6739, MT6750, MT6750S, MT6753, MT6757, MT6757C, MT6757CD, MT6757CH, MT6761, MT6762, MT6763, MT6765, MT6768, MT6769, MT6771, MT6779, MT6781, MT6785, MT6797, MT6833, MT6853, MT6853T, MT6873, MT6875, MT6877, MT6883, MT6885, MT6889, MT6893, MT8167, MT8168, MT8173, MT8185, MT8321, MT8362A, MT8365, MT8385, MT8666, MT8675, MT8695, MT8696, MT8765, MT8766, MT8768, MT8786, MT8788, MT8789, MT8791, MT8797Android 9.0, 10.0, 11.0, 12.0Not stated
GoogleAndroid9.0; 10.0; 11.0; 12.0Not 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
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
HighSuccess depends on conditions outside the attacker's control.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

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

Scoring systemScoreSeverityScored by
CVSS 3.17.0HighNVD
CVSS 2.04.4MediumNVD

Official description

In ion, there is a possible use after free due to a race condition. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation. Patch ID: ALPS06399915; Issue ID: ALPS06399901.

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

The underlying weakness: Time-of-check Time-of-use (TOCTOU) Race Condition

The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check.

How developers prevent this class of flaw

  • The most basic advice for TOCTOU vulnerabilities is to not perform a check before the use. This does not resolve the underlying issue of the execution of a function on a resource whose state and identity cannot be assured, but it does help to limit the false sense of security given by the check.
  • When the file being altered is owned by the current user and group, set the effective gid and uid to that of the current user and group when executing this statement.
  • Limit the interleaving of operations on files from multiple processes.

More Time-of-check Time-of-use (TOCTOU) Race Condition vulnerabilities (CWE-367)

Timeline

  1. CVE record published.
  2. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in MT6580, MT6735, MT6737, MT6739, MT6750, MT6750S, MT6753, MT6757, MT6757C, MT6757CD, MT6757CH, MT6761, MT6762, MT6763, MT6765, MT6768, MT6769, MT6771, MT6779, MT6781, MT6785, MT6797, MT6833, MT6853, MT6853T, MT6873, MT6875, MT6877, MT6883, MT6885, MT6889, MT6893, MT8167, MT8168, MT8173, MT8185, MT8321, MT8362A, MT8365, MT8385, MT8666, MT8675, MT8695, MT8696, MT8765, MT8766, MT8768, MT8786, MT8788, MT8789, MT8791, MT8797

All MT6580, MT6735, MT6737, MT6739, MT6750, MT6750S, MT6753, MT6757, MT6757C, MT6757CD, MT6757CH, MT6761, MT6762, MT6763, MT6765, MT6768, MT6769, MT6771, MT6779, MT6781, MT6785, MT6797, MT6833, MT6853, MT6853T, MT6873, MT6875, MT6877, MT6883, MT6885, MT6889, MT6893, MT8167, MT8168, MT8173, MT8185, MT8321, MT8362A, MT8365, MT8385, MT8666, MT8675, MT8695, MT8696, MT8765, MT8766, MT8768, MT8786, MT8788, MT8789, MT8791, MT8797 vulnerabilities

Recent Time-of-check Time-of-use (TOCTOU) Race Condition vulnerabilities

Spotted an error? Tell us.