What is CVE-2026-20502?

CVE-2026-20502 is a high-severity vulnerability in Mediatek Mt2718 Firmware, classified under Heap-based Buffer Overflow. CVSS score: 8.4/10. Published 2026-09-07.

How severe is CVE-2026-20502?

High severity. CVSS v3 base score is 8.4 out of 10.

Buffer overflow in Mediatek Mt2718 Firmware

CVE-2026-20502

In vdec, there is a possible out of bounds write 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: ALPS11262030; Issue ID: MSV-9196.

Vulnerability class: Buffer Overflow

Published 2026-09-07 · last modified 2026-09-09.

CVSS v3 metric

CVSS v3 base score 8.4 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.001 (2.2th percentile), scored 2026-10-23.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 2nd percentile — 2.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.001 · newest: 0.001 · change: +0.000

Affected products

Weakness classification (CWE)

CWE-122 — Heap-based Buffer Overflow

References

www.mediatek.com/product-security-bulletin/September-2026 (Vendor Advisory)

Frequently asked questions

What is CVE-2026-20502?: CVE-2026-20502 is a high-severity vulnerability in Mediatek Mt2718 Firmware, classified under Heap-based Buffer Overflow. CVSS score: 8.4/10. Published 2026-09-07.
How severe is CVE-2026-20502?: High severity. CVSS v3 base score is 8.4 out of 10.