CVE-2026-20521

Exploitation

Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.

SSVC decision

• ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
• AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
• Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

0.13% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 3.0% of scored records. A rank, not a probability.

NVD base score

8.4 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

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

NVD analysis status

Analyzed. NVD last modified this record on 2026-10-08.

Red Hat severity

No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2026-10-05 01:39Z24 DAYS AGO

Last updated

2026-10-06 03:55Z23 DAYS AGO

Reserved

2025-11-03

Assigning CNA

MediaTek

Record state

PUBLISHED

Severity

High (CVSS 8.4)

CNA CVSS vector

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

Weaknesses

• CWE-121Stack-based Buffer OverflowVariant

Data version

5.2

Document digest

777e5f3c272f4cf12c9a1d7a021644fdf740b5ff7e68c6ab960ad6998f391bfe

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