CVE-2026-20586: In vdec, there is a possible out of bounds write due to a missing bounds check

Routine

HIGH 8.8MITIGATEMITIGATEMITIGATE

CVE-2026-20586 is a high-severity flaw (CVSS 8.8) affecting mt8910 firmware, mt2718 firmware, mt6768 firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

In vdec, there is a possible out of bounds write due to a missing bounds check. This could lead to remote escalation of privilege with no additional execution privileges needed. User interaction is needed for exploitation. Patch ID: ALPS11383899; Issue ID: MSV-9614.

Why this priority

High severity

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	8.8 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.4% (top 67%)
CISA exploited list	No
Weakness	CWE-787
Published	2026-10-05
Last modified	2026-10-21

Publisher (CNA): MediaTek, Inc. · Vendor: mediatek

Last updated 2026-10-21 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-10-05 02:16 UTCPublished CVE record published
2026-10-21 08:16 UTCUpdated Record last modified

mediatek mt8910 firmware MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

mediatek mt2718 firmware MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

mediatek mt6768 firmware MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

mediatek mt6789 firmware MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

mediatek mt6769 firmware MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

mediatek mt6833 firmware MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-20586?

mt8910 firmware: mitigate or apply the listed mitigation; mt2718 firmware: mitigate or apply the listed mitigation; mt6768 firmware: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-20586 being exploited?

CVE-2026-20586 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-20586 affect?

CVE-2026-20586 affects mt8910 firmware, mt2718 firmware, mt6768 firmware. Severity is high (CVSS 8.8). In vdec, there is a possible out of bounds write due to a missing bounds check. This could lead to remote escalation of privilege with no additional execution privileges needed. User interaction is needed for exploitation. Patch ID: ALPS113

How urgent is CVE-2026-20586?

Priority 39/100. High severity

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CVE-2026-20475 MEDIUM 6.0 MITIGATE MITIGATE In display, there is a possible out of bounds write due to a missing bounds check
CVE-2026-20477 MEDIUM 6.0 MITIGATE MITIGATE In display, there is a possible out of bounds write due to a missing bounds check
CVE-2026-20544 MEDIUM 6.8 MITIGATE MITIGATE In meta, there is a possible out of bounds write due to a missing bounds check

References

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