System halt via incorrect secure stack selection
Published May 25, 2021 · Updated Oct 21, 2025
Out-of-bounds memory access in Arm Trusted Firmware-M 1.2 and earlier allows local users to halt or reset a system through secure calls. The secure SVC handler trusts EXC_RETURN.SPSEL without checking handler mode, selects PSP_S instead of MSP, and interprets unrelated stack data as an SVC request. A non-secure handler-mode caller can reliably trigger a recoverable halt or reset; only rare stack contents pass validation and enable secure-memory overwrite or log disclosure.
Summary
What happened
Out-of-bounds memory access in Arm Trusted Firmware-M 1.2 and earlier allows local users to halt or reset a system through secure calls. The secure SVC handler trusts EXC_RETURN.SPSEL without checking handler mode, selects PSP_S instead of MSP, and interprets unrelated stack data as an SVC request. A non-secure handler-mode caller can reliably trigger a recoverable halt or reset; only rare stack contents pass validation and enable secure-memory overwrite or log disclosure.
The record
- CVE
- CVE-2021-27562
- Published
- May 25, 2021
- Updated
- Oct 21, 2025
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-787, T1499.004
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- May 25, 2021CVE publishedPublication date reported by the CVE source.
- Oct 21, 2025Record updatedLatest update available in the CVE record.
Exploitability
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What is affected?
Affected products and versions are unavailable in this record.
Attacks
What attackers are doing with it
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Public exploit references
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Reported exploitation
- CISA Known Exploited Vulnerabilities entryknown exploited catalog
Technologies
Your stack
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Your stack
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