CVE-2026-11835: CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition in Caliptra Core ROM
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.
CVE-2026-11835: CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition in Caliptra Core ROM
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.
CVSS v4.0
Score 5.6medium
Affected software
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Technical Details
- Data Version
- 5.2
- Assigner Short Name
- Caliptra
- Date Reserved
- 2026-06-09T23:30:36.611Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a713369bf32cb7a347704bf
Added to database: 08/04/2026, 00:33:45 UTC
Last updated: 08/04/2026, 00:33:45 UTC
Views: 1
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