CVE Catalog

CVE-2026-11835

MediumCVSS 5.7
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.13%

2th percentile - higher than 2% of all known CVEs

Summary

A 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 modification between verification and loading into ICCM. Attestation continues to report the originally verified image digest, masking the compromise. Exploitation requires compromised MCU firmware with AXI manager access to unprotected SRAM.

Risk Assessment

An attacker could bypass secure boot, potentially leading to execution of malicious firmware in a trusted environment, compromising system integrity.

Recommendation

Apply patches provided by the Caliptra vendor and ensure MCU firmware is properly secured.

Related vulnerabilities

Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS