CVE-2026-11835

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.

CVSS

No CVSS.

References

Link	Resource
https://github.com/chipsalliance/caliptra-sw/security/advisories/GHSA-49mm-5gq5-v97f

Configurations

No configuration.

History

No history.

Information

Published : 2026-08-04 00:16

Updated : 2026-09-03 16:43

NVD link : CVE-2026-11835

Mitre link : CVE-2026-11835

CVE.ORG link : CVE-2026-11835

JSON object : View

Products Affected

No product.

CWE

CWE-20

Improper Input Validation

CWE-367

Time-of-check Time-of-use (TOCTOU) Race Condition

{"id": "CVE-2026-11835", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-11835", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-08-04T19:21:52.034967Z"}}], "cvssMetricV40": [{"type": "Secondary", "source": "b01ddd03-5ef6-483b-b2c5-acba77f1a554", "cvssData": {"Safety": "NOT_DEFINED", "version": "4.0", "Recovery": "NOT_DEFINED", "baseScore": 5.7, "Automatable": "NOT_DEFINED", "attackVector": "LOCAL", "baseSeverity": "MEDIUM", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/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", "exploitMaturity": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "userInteraction": "NONE", "attackComplexity": "HIGH", "attackRequirements": "PRESENT", "privilegesRequired": "HIGH", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "HIGH", "integrityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "availabilityRequirement": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "LOW", "confidentialityRequirement": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED"}}]}, "affected": [{"source": "b01ddd03-5ef6-483b-b2c5-acba77f1a554", "affectedData": [{"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"}]}], "published": "2026-08-04T00:16:40.047", "references": [{"url": "https://github.com/chipsalliance/caliptra-sw/security/advisories/GHSA-49mm-5gq5-v97f", "source": "b01ddd03-5ef6-483b-b2c5-acba77f1a554"}], "vulnStatus": "Awaiting Analysis", "weaknesses": [{"type": "Secondary", "source": "b01ddd03-5ef6-483b-b2c5-acba77f1a554", "description": [{"lang": "en", "value": "CWE-20"}, {"lang": "en", "value": "CWE-367"}]}], "descriptions": [{"lang": "en", "value": "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.\n\nThis issue affects Core ROM: 2.1.0 through 2.1.1."}], "lastModified": "2026-09-03T16:43:15.293", "sourceIdentifier": "b01ddd03-5ef6-483b-b2c5-acba77f1a554"}