{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-11835", "assignerOrgId": "b01ddd03-5ef6-483b-b2c5-acba77f1a554", "state": "PUBLISHED", "assignerShortName": "Caliptra", "dateReserved": "2026-06-09T23:30:36.611Z", "datePublished": "2026-08-04T00:03:23.278Z", "dateUpdated": "2026-08-04T00:05:12.892Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "b01ddd03-5ef6-483b-b2c5-acba77f1a554", "shortName": "Caliptra", "dateUpdated": "2026-08-04T00:05:12.892Z"}, "title": "Caliptra Update-Reset Secure-Boot Bypass via Attacker-Chosen AXI Staging Address (TOCTOU)", "datePublic": "2026-08-03T00:00:00.000Z", "problemTypes": [{"descriptions": [{"lang": "en", "cweId": "CWE-367", "description": "CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition", "type": "CWE"}]}, {"descriptions": [{"lang": "en", "cweId": "CWE-20", "description": "CWE-20 Improper Input Validation", "type": "CWE"}]}], "impacts": [{"capecId": "CAPEC-29", "descriptions": [{"lang": "en", "value": "CAPEC-29 Leveraging Time-of-Check and Time-of-Use (TOCTOU) Race Conditions"}]}], "affected": [{"vendor": "Caliptra", "product": "Core ROM", "collectionURL": "https://github.com/chipsalliance/caliptra-sw", "packageName": "Core ROM", "modules": ["UpdateResetFlow::run()"], "versions": [{"status": "affected", "version": "2.1.0", "lessThanOrEqual": "2.1.1", "versionType": "semver"}, {"status": "unaffected", "version": "2.1.2", "versionType": "semver"}], "defaultStatus": "unaffected"}], "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.", "supportingMedia": [{"type": "text/html", "base64": false, "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.<p>This issue affects Core ROM: 2.1.0 through 2.1.1.</p>"}]}], "tags": ["x_open-source"], "references": [{"url": "https://github.com/chipsalliance/caliptra-sw/security/advisories/GHSA-49mm-5gq5-v97f"}], "metrics": [{"format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}], "cvssV4_0": {"attackVector": "LOCAL", "attackComplexity": "HIGH", "attackRequirements": "PRESENT", "privilegesRequired": "HIGH", "userInteraction": "NONE", "vulnConfidentialityImpact": "LOW", "subConfidentialityImpact": "NONE", "vulnIntegrityImpact": "HIGH", "subIntegrityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "version": "4.0", "baseSeverity": "MEDIUM", "baseScore": 5.6, "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"}}], "source": {"discovery": "INTERNAL"}, "x_generator": {"engine": "Vulnogram 1.0.2"}}}}

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