Authentication bypass using an alternate path or channel in MediaTek products - CVE-2026-20459
Published: July 1, 2026
Vulnerability identifier: #VU136041
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-20459
CWE-ID: CWE-288
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: MediaTek
Affected software:
MT6993
MT8766
MT8765
MT8755
MT8678
MT8676
MT8675
MT8673
MT8668
MT8667
MT8666
MT8766R
MT6991
MT6990
MT6989
MT6988
MT6986D
MT6986
MT6985
MT6983
MT6982
MT8791T
MT8893
MT8883
MT8873
MT8863
MT8798
MT8796
MT8795T
MT8793
MT8792
MT6980
MT8791
MT8789
MT8788E
MT8788
MT8786
MT8781
MT8775
MT8771
MT8768
MT6769
MT6835
MT6833
MT6813
MT6789
MT6783
MT6771
MT6855
MT6768
MT6767
MT6765
MT6763
MT6762
MT6761
MT6739
MT2737
MT2735
MT6899
MT6897
MT6896
MT6895
MT6890
MT6886
MT2716
MT6881
MT6880
MT6879
MT6878
MT6858
MT8797
MT6853
MT6785
MT6781
MT6779
MT6885
MT6893
MT6891
MT6889
MT6883
MT6877
MT6875
MT6873
MT6993
MT8766
MT8765
MT8755
MT8678
MT8676
MT8675
MT8673
MT8668
MT8667
MT8666
MT8766R
MT6991
MT6990
MT6989
MT6988
MT6986D
MT6986
MT6985
MT6983
MT6982
MT8791T
MT8893
MT8883
MT8873
MT8863
MT8798
MT8796
MT8795T
MT8793
MT8792
MT6980
MT8791
MT8789
MT8788E
MT8788
MT8786
MT8781
MT8775
MT8771
MT8768
MT6769
MT6835
MT6833
MT6813
MT6789
MT6783
MT6771
MT6855
MT6768
MT6767
MT6765
MT6763
MT6762
MT6761
MT6739
MT2737
MT2735
MT6899
MT6897
MT6896
MT6895
MT6890
MT6886
MT2716
MT6881
MT6880
MT6879
MT6878
MT6858
MT8797
MT6853
MT6785
MT6781
MT6779
MT6885
MT6893
MT6891
MT6889
MT6883
MT6877
MT6875
MT6873
Detailed vulnerability description
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to authentication bypass using an alternate path or channel in the modem when processing input. A local user can use an alternate path or channel to cause a denial of service.
How to mitigate CVE-2026-20459
Install security update from vendor's website.