CVE-2021-27562: Arm Trusted Firmware Out-of-Bounds Write Vulnerability

How to check if you are exposed to CVE-2021-27562

1. Find every Arm Trusted Firmware system you or your clients run, including ones exposed to the internet. Those come first: CISA only lists flaws attackers are already using.
2. Compare each version with the fixed versions in the vendor advisory. Where no fix exists yet, apply the vendor’s mitigation or take the system off the internet.
3. Run a credentialed vulnerability scan to catch the systems you missed, then check that the next scan no longer reports CVE-2021-27562.

US federal agencies had to fix this by 2021-11-17. Everyone else should treat that deadline as a guide: if it has passed, this is overdue.

Affected versions

Versions the National Vulnerability Database lists as vulnerable to CVE-2021-27562. Check the vendor advisory for the exact fixed builds before you sign anything off.

Timeline

1. 2021-05-25 · Published in the National Vulnerability Database
2. 2021-11-03 · Added to CISA's Known Exploited Vulnerabilities catalog, 162 days after it was published
3. 2021-11-17 · Fix-by date for US federal agencies, passed 1,810 days ago

Weakness type

• CWE-787

More exploited Arm vulnerabilities

CISA lists 9 exploited Arm vulnerabilities. The closest matches:

• CVE-2024-4610Arm Mali GPU Kernel Driver Use-After-Free VulnerabilityAdded 2024-06-12
• CVE-2023-4211Arm Mali GPU Kernel Driver Use-After-Free VulnerabilityAdded 2023-10-03
• CVE-2021-29256Arm Mali GPU Kernel Driver Use-After-Free VulnerabilityAdded 2023-07-07
• CVE-2023-26083Arm Mali GPU Kernel Driver Information Disclosure VulnerabilityAdded 2023-04-07
• CVE-2022-38181Arm Mali GPU Kernel Driver Use-After-Free VulnerabilityAdded 2023-03-30
• CVE-2022-22706Arm Mali GPU Kernel Driver Unspecified VulnerabilityAdded 2023-03-30
• CVE-2021-28664Arm Mali Graphics Processing Unit (GPU) Unspecified VulnerabilityAdded 2021-11-03
• CVE-2021-28663Arm Mali Graphics Processing Unit (GPU) Use-After-Free VulnerabilityAdded 2021-11-03

Keep going

• All exploited CVEs
• Check another CVE
• What is CISA KEV?
• What is EPSS?

Sources: CISA Known Exploited Vulnerabilities catalog (version 2026.10.30); EPSS data from FIRST.org; CVSS and descriptions from the NIST National Vulnerability Database. Checked 2026-11-01. This product uses the NVD API but is not endorsed or certified by the NVD.