PatchSiren cyber security CVE debrief
CVE-2021-27562 Arm CVE debrief
CVE-2021-27562 is an out-of-bounds write in Arm Trusted Firmware. CISA added it to the Known Exploited Vulnerabilities catalog on 2021-11-03 and set a remediation due date of 2021-11-17, so it should be treated as an urgent patching item for any affected environment.
- Vendor
- Arm
- Product
- Trusted Firmware
- CVSS
- Unknown
- CISA KEV
- Listed
- Original CVE published
- 2021-11-03
- Original CVE updated
- 2021-11-03
- Advisory published
- 2021-11-03
- Advisory updated
- 2021-11-03
Who should care
Security, firmware, and platform teams that build, ship, or maintain systems containing Arm Trusted Firmware should care most, along with vulnerability management teams tracking CISA KEV items and device owners responsible for embedded or boot firmware updates.
Technical summary
The supplied records identify the issue as an out-of-bounds write affecting Arm Trusted Firmware. The corpus does not include affected versions, code paths, impact scope, or exploit details beyond the CISA KEV designation, so remediation should be driven by vendor guidance and inventory of deployed firmware images.
Defensive priority
Urgent
Recommended defensive actions
- Apply the vendor-recommended update or mitigation for Arm Trusted Firmware as soon as possible.
- Inventory devices, images, and build pipelines that include Arm Trusted Firmware to confirm exposure.
- Validate that firmware, bootloader, and platform update processes reach all affected assets.
- Track any devices that cannot be updated immediately and apply compensating controls until remediation is complete.
- Use the official CISA KEV and vendor/CVE records to confirm current guidance before and after patching.
Evidence notes
CISA's Known Exploited Vulnerabilities JSON feed lists this item as 'Arm Trusted Firmware Out-of-Bounds Write Vulnerability' for vendor Arm and product Trusted Firmware, with dateAdded 2021-11-03, dueDate 2021-11-17, and requiredAction 'Apply updates per vendor instructions.' The supplied corpus also provides official CVE and NVD record links, but no additional technical specifics are included in the source text here.
Official resources
-
CVE-2021-27562 CVE record
CVE.org
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CVE-2021-27562 NVD detail
NVD
-
CISA Known Exploited Vulnerabilities catalog
CISA - Apply updates per vendor instructions.
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Source item URL
cisa_kev
Publicly disclosed and published on 2021-11-03; CISA added the issue to the KEV catalog the same day and set the remediation due date to 2021-11-17.