MT6761, MT6762, MT6765, MT6768, MT6769…: Use After Free
CVE-2022-21745 is a high-severity use after free vulnerability in MT6761, MT6762, MT6765, MT6768, MT6769, MT6779, MT6781, MT6785, MT6789, MT6833, MT6853, MT6853T, MT6873, MT6875, MT6877, MT6879, MT6883, MT6885, MT6889, MT6891, MT6893, MT6895, MT6983, MT6985, MT8167S, MT8168, MT8175, MT8183, MT8185, MT8362A, MT8365, MT8385, MT8667, MT8675, MT8695, MT8696, MT8766, MT8768, MT8786, MT8788, MT8789, MT8791, MT8797 from MediaTek, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited from the same local network by an unauthenticated attacker, without any action from a user. Affected MT6761, MT6762, MT6765, MT6768, MT6769, MT6779, MT6781, MT6785, MT6789, MT6833, MT6853, MT6853T, MT6873, MT6875, MT6877, MT6879, MT6883, MT6885, MT6889, MT6891, MT6893, MT6895, MT6983, MT6985, MT8167S, MT8168, MT8175, MT8183, MT8185, MT8362A, MT8365, MT8385, MT8667, MT8675, MT8695, MT8696, MT8766, MT8768, MT8786, MT8788, MT8789, MT8791, MT8797 versions: Android 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 0.4% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of MT6761, MT6762, MT6765, MT6768, MT6769, MT6779, MT6781, MT6785, MT6789, MT6833, MT6853, MT6853T, MT6873, MT6875, MT6877, MT6879, MT6883, MT6885, MT6889, MT6891, MT6893, MT6895, MT6983, MT6985, MT8167S, MT8168, MT8175, MT8183, MT8185, MT8362A, MT8365, MT8385, MT8667, MT8675, MT8695, MT8696, MT8766, MT8768, MT8786, MT8788, MT8789, MT8791, MT8797 you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on corp.mediatek.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| MediaTek | MT6761, MT6762, MT6765, MT6768, MT6769, MT6779, MT6781, MT6785, MT6789, MT6833, MT6853, MT6853T, MT6873, MT6875, MT6877, MT6879, MT6883, MT6885, MT6889, MT6891, MT6893, MT6895, MT6983, MT6985, MT8167S, MT8168, MT8175, MT8183, MT8185, MT8362A, MT8365, MT8385, MT8667, MT8675, MT8695, MT8696, MT8766, MT8768, MT8786, MT8788, MT8789, MT8791, MT8797 | Android 10.0, 11.0, 12.0 | Not stated |
| Android | 10.0; 11.0; 12.0 | Not 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
- AdjacentThe attacker must be on the same local network segment.
- 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:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.8 | High | NVD |
| CVSS 2.0 | 8.3 | High | NVD |
Official description
In WIFI Firmware, there is a possible memory corruption due to a use after free. This could lead to remote escalation of privilege, when devices are connecting to the attacker-controllable Wi-Fi hotspot, with no additional execution privileges needed. User interaction is not needed for exploitation. Patch ID: ALPS06468872; Issue ID: ALPS06468872.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use After Free
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
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- 7.8 High severity
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