CISA KEV entry
CVE-2021-27562Arm Trusted Firmware Out-of-Bounds Write Vulnerability
Arm Trusted Firmware. Added to the CISA Known Exploited Vulnerabilities catalogue on 3 November 2021.
Data status: a source is stale
Last synced CISA catalogue version 2026.11.04 (released 4 November 2026) 1,768 entries Updated manually
- Date added
- 2021-11-03
- Federal due date
- 2021-11-17 14 days after it was added; passed at the sync of 2026-11-05
- Known ransomware use
- Unknown
- Forensic triage (BOD 26-04)
- No
- CVSS
- 5.5 Medium CVSS 3.1, scored by nvd@nist.gov
- EPSS
- 3.06% percentile 87.6, scored 2026-11-04
- CISA SSVC
- Exploitation active, automatable no, technical impact partial
- NVD status
- Analyzed published 2021-05-25, 162 days before the KEV listing
BOD 26-04 remediation window
With CISA's SSVC answers for this CVE (automatable: no, technical impact: partial), BOD 26-04 Table 1 gives 14 days on a publicly exposed asset (row 4) and 14 days on an asset that is not publicly exposed (row 12) S06. The catalogue due date, 14 days after the date added, was set before BOD 26-04 took effect on 10 June 2026 S06. The directive binds US federal civilian executive branch agencies only.
What CISA says
Short description
Arm Trusted Firmware contains an out-of-bounds write vulnerability allowing the non-secure (NS) world to trigger a system halt, overwrite secure data, or print out secure data when calling secure functions under the non-secure processing environment (NSPE) handler mode. This vulnerability affects Yealink Device Management servers.
Required action
Apply updates per vendor instructions.
Notes
https://nvd.nist.gov/vuln/detail/CVE-2021-27562
CWE in the catalogue
CWE-787
Official links
- CISA KEV catalogue entry cisa.gov
- NVD record nvd.nist.gov
Vendor advisory and patch links
References NVD tags Vendor Advisory or Patch, exactly as NVD lists them.
- https://developer.arm.com/support/arm-security-updates Vendor Advisory
Links in CISA's notes
NVD details
- CWE (NVD)
- CWE-787 by nvd@nist.gov
- CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H- CVSS versions in NVD
- V2, V31
- Last modified in NVD
- 2026-06-17T03:45:08.407
Where each value comes from
| Field | Source | Fetched, UTC | State |
|---|---|---|---|
| Catalogue fields | CISA KEV JSON, version 2026.11.04 | 2026-11-05 11:38 | current |
| NVD published, status, CVSS, CWE, vendor links | NVD CVE API 2.0; CVSS: NVD (nvd@nist.gov) | 2026-11-03 12:37 | current at 2026-11-05 11:38 |
| EPSS | FIRST EPSS API, scores of 2026-11-04 | 2026-11-05 11:38 | current |
| CISA SSVC | CISA ADP (via NVD), record of 2025-02-04 | 2026-11-03 12:37 | current |
This product uses data from the NVD API but is not endorsed or certified by the NVD. CISA does not endorse Sysprobs. Methodology.