CVE-2026-20521

HIGH

Published Oct 5, 2026 Modified Oct 8, 2026 CWE-121

Description

In Video HAL, there is a possible escalation of privilege due to a missing bounds check. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation. Patch ID: ALPS11375674; Issue ID: MSV-9571.

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CVSS v3.1 Score

8.4

HIGH

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0014

Probability of exploitation

0.03%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-121 CWE-121

Affected Products

Vendor	Product	Versions
mediatek	mt8910_firmware	All
mediatek	mt8910	All
mediatek	mt2718_firmware	All
mediatek	mt2718	All
mediatek	mt6768_firmware	All
mediatek	mt6768	All
mediatek	mt6769_firmware	All
mediatek	mt6769	All
mediatek	mt6781_firmware	All
mediatek	mt6781	All
mediatek	mt6789_firmware	All
mediatek	mt6789	All
mediatek	mt6833_firmware	All
mediatek	mt6833	All
mediatek	mt6835_firmware	All
mediatek	mt6835	All
mediatek	mt6853_firmware	All
mediatek	mt6853	All
mediatek	mt6855_firmware	All
mediatek	mt6855	All
mediatek	mt6858_firmware	All
mediatek	mt6858	All
mediatek	mt6877_firmware	All
mediatek	mt6877	All
mediatek	mt6878_firmware	All
mediatek	mt6878	All
mediatek	mt6879_firmware	All
mediatek	mt6879	All
mediatek	mt6881_firmware	All
mediatek	mt6881	All
mediatek	mt6883_firmware	All
mediatek	mt6883	All
mediatek	mt6885_firmware	All
mediatek	mt6885	All
mediatek	mt6886_firmware	All
mediatek	mt6886	All
mediatek	mt6889_firmware	All
mediatek	mt6889	All
mediatek	mt6893_firmware	All
mediatek	mt6893	All
mediatek	mt6895_firmware	All
mediatek	mt6895	All
mediatek	mt6897_firmware	All
mediatek	mt6897	All
mediatek	mt6899_firmware	All
mediatek	mt6899	All
mediatek	mt6983_firmware	All
mediatek	mt6983	All
mediatek	mt6985_firmware	All
mediatek	mt6985	All
mediatek	mt6989_firmware	All
mediatek	mt6989	All
mediatek	mt6991_firmware	All
mediatek	mt6991	All
mediatek	mt6993_firmware	All
mediatek	mt6993	All
mediatek	mt8126_firmware	All
mediatek	mt8126	All
mediatek	mt8171_firmware	All
mediatek	mt8171	All
mediatek	mt8186_firmware	All
mediatek	mt8186	All
mediatek	mt8188_firmware	All
mediatek	mt8188	All
mediatek	mt8189_firmware	All
mediatek	mt8189	All
mediatek	mt8195_firmware	All
mediatek	mt8195	All
mediatek	mt8196_firmware	All
mediatek	mt8196	All
mediatek	mt8367_firmware	All
mediatek	mt8367	All
mediatek	mt8391_firmware	All
mediatek	mt8391	All
mediatek	mt8395_firmware	All
mediatek	mt8395	All
mediatek	mt8668_firmware	All
mediatek	mt8668	All
mediatek	mt8676_firmware	All
mediatek	mt8676	All
mediatek	mt8678_firmware	All
mediatek	mt8678	All
mediatek	mt8695_firmware	All
mediatek	mt8695	All
mediatek	mt8696_firmware	All
mediatek	mt8696	All
mediatek	mt8781_firmware	All
mediatek	mt8781	All
mediatek	mt8788e_firmware	All
mediatek	mt8788e	All
mediatek	mt8792_firmware	All
mediatek	mt8792	All
mediatek	mt8793_firmware	All
mediatek	mt8793	All
mediatek	mt8799_firmware	All
mediatek	mt8799	All

References

Advisories & Patches

https://www.mediatek.com/product-security-bulletin/October-2026

Frequently Asked Questions

What is CVE-2026-20521? +

How severe is CVE-2026-20521? +

CVE-2026-20521 has a CVSS v3.1 score of 8.4 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0014, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-20521? +

CVE-2026-20521 affects products from mediatek, specifically: mt2718, mt2718_firmware, mt6768, mt6768_firmware, mt6769, mt6769_firmware, mt6781, mt6781_firmware, mt6789, mt6789_firmware, mt6833, mt6833_firmware, mt6835, mt6835_firmware, mt6853, mt6853_firmware, mt6855, mt6855_firmware, mt6858, mt6858_firmware, mt6877, mt6877_firmware, mt6878, mt6878_firmware, mt6879, mt6879_firmware, mt6881, mt6881_firmware, mt6883, mt6883_firmware, mt6885, mt6885_firmware, mt6886, mt6886_firmware, mt6889, mt6889_firmware, mt6893, mt6893_firmware, mt6895, mt6895_firmware, mt6897, mt6897_firmware, mt6899, mt6899_firmware, mt6983, mt6983_firmware, mt6985, mt6985_firmware, mt6989, mt6989_firmware, mt6991, mt6991_firmware, mt6993, mt6993_firmware, mt8126, mt8126_firmware, mt8171, mt8171_firmware, mt8186, mt8186_firmware, mt8188, mt8188_firmware, mt8189, mt8189_firmware, mt8195, mt8195_firmware, mt8196, mt8196_firmware, mt8367, mt8367_firmware, mt8391, mt8391_firmware, mt8395, mt8395_firmware, mt8668, mt8668_firmware, mt8676, mt8676_firmware, mt8678, mt8678_firmware, mt8695, mt8695_firmware, mt8696, mt8696_firmware, mt8781, mt8781_firmware, mt8788e, mt8788e_firmware, mt8792, mt8792_firmware, mt8793, mt8793_firmware, mt8799, mt8799_firmware, mt8910, mt8910_firmware. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-20521? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.