What’s Vulnerable › Vulnerabilities
CVE-2026-11835: Caliptra Update-Reset Secure-Boot Bypass via Attacker-Chosen AXI Staging Address (TOCTOU)
- Severity: medium (CVSS 5.7 v4.0)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.1% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-08-04 · updated 2026-10-23
- Weakness: CWE-20
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.
Affected products
- Caliptra Core ROM: from 2.1.0 through 2.1.1
References
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