CVE-2026-11835 Caliptra Update-Reset Secure-Boot Bypass via Attacker-Chosen AXI Staging Address (TOCTOU)
A compromised local attacker can bypass secure boot in Caliptra Core ROM by exploiting a TOCTOU race condition to modify firmware during loading.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-11835?
CVE-2026-11835 is a medium-severity vulnerability in Caliptra Core ROM, published on 4 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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.
Which versions are affected by CVE-2026-11835?
How do I fix CVE-2026-11835?
No fix has been published for CVE-2026-11835 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-11835 being exploited?
There is no known exploitation of CVE-2026-11835 in the wild and no public exploit code.
Sources
Also known as GHSA-49mm-5gq5-v97f.