Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2021-27562 is a medium-severity Out-of-bounds Write (CWE-787) vulnerability in Trustedfirmware Trusted Firmware-M. Its CVSS base score is 5.5 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Security Account Manager (T1003.002); ranked in the top 13% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
Arm Trusted Firmware M through version 1.2 contains an out-of-bounds write vulnerability (CWE-787) that manifests when non-secure world code invokes secure functions while executing in NSPE handler mode. The flaw allows the non-secure caller to trigger a system halt, corrupt secure memory regions, or cause secure data to be printed to non-secure outputs.
A local attacker with low privileges in the non-secure world can exploit the issue by crafting calls to secure services under handler mode, resulting in denial of service or leakage and modification of protected assets. The CVSS 5.5 vector reflects local access, low attack complexity, and a primary impact on availability with secondary risks to confidentiality and integrity.
Arm security advisories and the TF-M project advisory on svc_caller_sp_fetching_vulnerability describe the defect and direct users to patched firmware releases. The vulnerability is also catalogued in CISA's Known Exploited Vulnerabilities list, indicating confirmed in-the-wild exploitation against affected devices.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2021-14313
Vulnerability Data
In Arm Trusted Firmware M through 1.2, the NS world may trigger a system halt, an overwrite of secure data, or the printing out of secure data when calling secure functions under the NSPE handler mode.
- CWE(s)
- KEV Date Added
- 03 November 2021
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Out-of-bounds writes that corrupt control flow or inject shellcode are rendered non-executable by the same memory protections.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Vulnerability scanning and recording can discover out-of-bounds write flaws so they can be remediated.
Patching or replacing vulnerable software directly eliminates known instances of this coding weakness.
Secure-development practices (static analysis, bounds checking, code review) are the primary means of preventing out-of-bounds writes.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.