CVE-2026-11835

Summary

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.

Affected Software

VendorProductVersion RangeStatus
CaliptraCore ROM2.1.0 <= 2.1.1affected
CaliptraCore ROM2.1.2unaffected

Weaknesses

  • CWE-367: CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition
  • CWE-20: CWE-20 Improper Input Validation

References