CVE-2026-20538: In Modem, there is a possible out of bounds read due to a missing permission check
20
Routine
MEDIUM 5.3MITIGATEMITIGATEMITIGATE
CVE-2026-20538 is a medium-severity flaw (CVSS 5.3) affecting mt2716 firmware, mt2735 firmware, mt2737 firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
In Modem, there is a possible out of bounds read due to a missing permission check. This could lead to remote denial of service, if a UE has connected to a rogue base station controlled by the attacker, with no additional execution privileges needed. User interaction is not needed for exploitation. Patch ID: MOLY01774038; Issue ID: MSV-8914.
Why this priority
No elevated risk signals yet
No fix is published yet: follow the downgrade or mitigation steps.
Last updated 2026-10-09 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
Published CVE record published
Updated Record last modified
mediatek mt2716 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 mt2735 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 mt2737 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 mt6739 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 mt6761 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 mt6762 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 sourceNVD · 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-2026-20538?
mt2716 firmware: mitigate or apply the listed mitigation; mt2735 firmware: mitigate or apply the listed mitigation; mt2737 firmware: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.
Is CVE-2026-20538 being exploited?
CVE-2026-20538 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-2026-20538 affect?
CVE-2026-20538 affects mt2716 firmware, mt2735 firmware, mt2737 firmware. Severity is medium (CVSS 5.3). In Modem, there is a possible out of bounds read due to a missing permission check. This could lead to remote denial of service, if a UE has connected to a rogue base station controlled by the attacker, with no additional execution privileg
How urgent is CVE-2026-20538?
Priority 20/100. No elevated risk signals yet.
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