CVE-2026-11835
Caliptra Update-Reset Secure-Boot Bypass via Attacker-Chosen AXI Staging Address (TOCTOU)
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.
INFO
Published Date :
Aug. 4, 2026, 12:16 a.m.
Last Modified :
Aug. 4, 2026, 12:16 a.m.
Remotely Exploit :
No
Source :
b01ddd03-5ef6-483b-b2c5-acba77f1a554
Affected Products
The following products are affected by CVE-2026-11835
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | MEDIUM | b01ddd03-5ef6-483b-b2c5-acba77f1a554 | ||||
| CVSS 4.0 | MEDIUM | b01ddd03-5ef6-483b-b2c5-acba77f1a554 |
Solution
- Update Caliptra Core ROM firmware to the latest version.
- Validate AXI staging addresses against base address.
- Implement strict input validation for boot process.
- Ensure integrity checks cover all loading stages.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-11835.
| URL | Resource |
|---|---|
| https://github.com/chipsalliance/caliptra-sw/security/advisories/GHSA-49mm-5gq5-v97f |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-11835 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-11835
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-11835 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-11835 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by b01ddd03-5ef6-483b-b2c5-acba77f1a554
Aug. 04, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'Caliptra', 'modules': ['UpdateResetFlow::run()'], 'product': 'Core ROM', 'versions': [{'status': 'affected', 'version': '2.1.0', 'versionType': 'semver', 'lessThanOrEqual': '2.1.1'}, {'status': 'unaffected', 'version': '2.1.2', 'versionType': 'semver'}], 'packageName': 'Core ROM', 'collectionURL': 'https://github.com/chipsalliance/caliptra-sw', 'defaultStatus': 'unaffected'}] Added 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. Added CVSS V4.0 AV:L/AC:H/AT:P/PR:H/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-20 Added CWE CWE-367 Added Reference https://github.com/chipsalliance/caliptra-sw/security/advisories/GHSA-49mm-5gq5-v97f