CVE-2026-11835

Secure-boot bypass via unchecked AXI staging address

Published Aug 4, 2026 · Updated Aug 4, 2026

Secure-boot bypass in Caliptra Core ROM 2.1.0 through 2.1.1 allows local users to execute modified firmware during subsystem update reset. UpdateResetFlow::run() accepts the firmware address from per-command mailbox fields without checking it against SS_EXTERNAL_STAGING_AREA_BASE_ADDR and does not reverify the ICCM image after loading. Exploitation requires compromised MCU firmware with AXI-manager access to unprotected SRAM, and attestation continues to report the originally verified digest.

CVSS severity5.6
Medium
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Secure-boot bypass in Caliptra Core ROM 2.1.0 through 2.1.1 allows local users to execute modified firmware during subsystem update reset. UpdateResetFlow::run() accepts the firmware address from per-command mailbox fields without checking it against SS_EXTERNAL_STAGING_AREA_BASE_ADDR and does not reverify the ICCM image after loading. Exploitation requires compromised MCU firmware with AXI-manager access to unprotected SRAM, and attestation continues to report the originally verified digest.

The record

CVE
CVE-2026-11835
Published
Aug 4, 2026
Updated
Aug 4, 2026
Vendor
Caliptra
Product
Core ROM
Classifications
CWE-20, CWE-367, CAPEC-29, T1553
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Aug 4, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.1.0 <=2.1.1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Caliptra · Core ROMversion=2.1.0 <=2.1.1

Published CVSS scores

5.6CaliptraCVSS:4.0/AV:L/AC:H/AT:P/PR:H/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N
5.7GitHubCVSS:4.0/AV:L/AC:H/AT:P/PR:H/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
CWE-367Time-of-check Time-of-use (TOCTOU) Race Condition
CAPEC-29Leveraging Time-of-Check and Time-of-Use (TOCTOU) Race Conditions
T1553Subvert Trust Controls

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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