CyberSecBulletin
CVE-2022-20083NVD status: Modified

MT2731, MT2735, MT6297, MT6725, MT6735…: Out-of-bounds Write

Published Updated By the CyberSecBulletin desk

CVE-2022-20083 is a critical-severity out-of-bounds write vulnerability in MT2731, MT2735, MT6297, MT6725, MT6735, MT6737, MT6739, MT6750, MT6750S, MT6755, MT6757, MT6757P, MT6758, MT6761, MT6762, MT6762D, MT6762M, MT6763, MT6765, MT6765T, MT6767, MT6768, MT6769, MT6769T, MT6769Z, MT6771, MT6775, MT6779, MT6781, MT6783, MT6785, MT6785T, MT6789, MT6797, MT6799, MT6833, MT6853, MT6855, MT6873, MT6875, MT6877, MT6879, MT6880, MT6883, MT6885, MT6889, MT6890, MT6891, MT6893, MT6895, MT6983, MT8666, MT8667, MT8675, MT8735A, MT8735B, MT8765, MT8766, MT8768, MT8771, MT8781, MT8786, MT8788, MT8789, MT8791, MT8797 from MediaTek, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected MT2731, MT2735, MT6297, MT6725, MT6735, MT6737, MT6739, MT6750, MT6750S, MT6755, MT6757, MT6757P, MT6758, MT6761, MT6762, MT6762D, MT6762M, MT6763, MT6765, MT6765T, MT6767, MT6768, MT6769, MT6769T, MT6769Z, MT6771, MT6775, MT6779, MT6781, MT6783, MT6785, MT6785T, MT6789, MT6797, MT6799, MT6833, MT6853, MT6855, MT6873, MT6875, MT6877, MT6879, MT6880, MT6883, MT6885, MT6889, MT6890, MT6891, MT6893, MT6895, MT6983, MT8666, MT8667, MT8675, MT8735A, MT8735B, MT8765, MT8766, MT8768, MT8771, MT8781, MT8786, MT8788, MT8789, MT8791, MT8797 versions: Modem LR9, LR11, LR12, LR12A, LR13, NR15, NR16. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 2.82% chance of exploitation within 30 days, higher than 87% of scored CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Check which version of MT2731, MT2735, MT6297, MT6725, MT6735, MT6737, MT6739, MT6750, MT6750S, MT6755, MT6757, MT6757P, MT6758, MT6761, MT6762, MT6762D, MT6762M, MT6763, MT6765, MT6765T, MT6767, MT6768, MT6769, MT6769T, MT6769Z, MT6771, MT6775, MT6779, MT6781, MT6783, MT6785, MT6785T, MT6789, MT6797, MT6799, MT6833, MT6853, MT6855, MT6873, MT6875, MT6877, MT6879, MT6880, MT6883, MT6885, MT6889, MT6890, MT6891, MT6893, MT6895, MT6983, MT8666, MT8667, MT8675, MT8735A, MT8735B, MT8765, MT8766, MT8768, MT8771, MT8781, 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.
  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
MediaTekMT2731, MT2735, MT6297, MT6725, MT6735, MT6737, MT6739, MT6750, MT6750S, MT6755, MT6757, MT6757P, MT6758, MT6761, MT6762, MT6762D, MT6762M, MT6763, MT6765, MT6765T, MT6767, MT6768, MT6769, MT6769T, MT6769Z, MT6771, MT6775, MT6779, MT6781, MT6783, MT6785, MT6785T, MT6789, MT6797, MT6799, MT6833, MT6853, MT6855, MT6873, MT6875, MT6877, MT6879, MT6880, MT6883, MT6885, MT6889, MT6890, MT6891, MT6893, MT6895, MT6983, MT8666, MT8667, MT8675, MT8735A, MT8735B, MT8765, MT8766, MT8768, MT8771, MT8781, MT8786, MT8788, MT8789, MT8791, MT8797Modem LR9, LR11, LR12, LR12A, LR13, NR15, NR16Not stated
MediaTekLr11Not specified in the recordNot stated
MediaTekLr12Not specified in the recordNot stated
MediaTekLr12aNot specified in the recordNot stated
MediaTekLr13Not specified in the recordNot stated
MediaTekLr9Not specified in the recordNot stated
MediaTekNr15Not specified in the recordNot stated
MediaTekNr16Not 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
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:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.19.8CriticalNVD
CVSS 2.010.0HighNVD

Official description

In Modem 2G/3G CC, there is a possible out of bounds write due to a missing bounds check. This could lead to remote code execution when decoding combined FACILITY with no additional execution privileges needed. User interaction is not needed for exploitation. Patch ID: MOLY00803883; Issue ID: MOLY00803883.

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

The underlying weakness: Out-of-bounds Write

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

How developers prevent this class of flaw

  • Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples include the Safe C String Library (SafeStr) by Messier and Viega, and the Strsafe.h library from Microsoft. These libraries provide safer versions of overflow-prone string-handling functions.
  • Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.

More Out-of-bounds Write vulnerabilities (CWE-787)

Timeline

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

References

Other vulnerabilities in MT2731, MT2735, MT6297, MT6725, MT6735, MT6737, MT6739, MT6750, MT6750S, MT6755, MT6757, MT6757P, MT6758, MT6761, MT6762, MT6762D, MT6762M, MT6763, MT6765, MT6765T, MT6767, MT6768, MT6769, MT6769T, MT6769Z, MT6771, MT6775, MT6779, MT6781, MT6783, MT6785, MT6785T, MT6789, MT6797, MT6799, MT6833, MT6853, MT6855, MT6873, MT6875, MT6877, MT6879, MT6880, MT6883, MT6885, MT6889, MT6890, MT6891, MT6893, MT6895, MT6983, MT8666, MT8667, MT8675, MT8735A, MT8735B, MT8765, MT8766, MT8768, MT8771, MT8781, MT8786, MT8788, MT8789, MT8791, MT8797

All MT2731, MT2735, MT6297, MT6725, MT6735, MT6737, MT6739, MT6750, MT6750S, MT6755, MT6757, MT6757P, MT6758, MT6761, MT6762, MT6762D, MT6762M, MT6763, MT6765, MT6765T, MT6767, MT6768, MT6769, MT6769T, MT6769Z, MT6771, MT6775, MT6779, MT6781, MT6783, MT6785, MT6785T, MT6789, MT6797, MT6799, MT6833, MT6853, MT6855, MT6873, MT6875, MT6877, MT6879, MT6880, MT6883, MT6885, MT6889, MT6890, MT6891, MT6893, MT6895, MT6983, MT8666, MT8667, MT8675, MT8735A, MT8735B, MT8765, MT8766, MT8768, MT8771, MT8781, MT8786, MT8788, MT8789, MT8791, MT8797 vulnerabilities

Recent Out-of-bounds Write vulnerabilities

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