CVE-2026-11835
Caliptra Update-Reset Secure-Boot Bypass via Attacker-Chosen AXI Staging Address (TOCTOU)
- State
- Published
- Severity
- 5.6 Medium
- Published
- Aug 4, 2026
- Updated
- Aug 4, 2026
- Reserved
- Jun 9, 2026
Description
Time-of-check time-of-use (TOCTOU) vulnerability combined with missing input validation in Caliptra Core ROM (UpdateResetFlow::run()) in subsystem mode allows a compromised local attacker to silently bypass secure boot by supplying an AXI staging address that is not validated against the strap-configured SS_EXTERNAL_STAGING_AREA_BASE_ADDR, enabling firmware to be modified between verification and loading into ICCM. Attestation continues to report the originally verified image digest, masking the compromise. Exploitation requires a compromised MCU firmware with AXI manager access to unprotected SRAM reachable by Caliptra.
This issue affects Core ROM: 2.1.0 through 2.1.1.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 5.6 Medium | CVSS:4.0/AV:L/AC:H/AT:P/PR:H/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N | Caliptra |
Weaknesses
Affected Products
| Product | Versions |
|---|---|
Core ROMCaliptra |
|
References
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