{"id":"CVE-2021-27562","published":"2021-05-25T19:15:07Z","modified":"2026-06-17T03:45:08Z","title":"Arm Trusted Firmware Out-of-Bounds Write Vulnerability","vendor":"Arm","product":"Trusted Firmware","tier":"core","eol":null,"description":{"text":"In Arm Trusted Firmware M through 1.2, the NS world may trigger a system halt, an overwrite of secure data, or the printing out of secure data when calling secure functions under the NSPE handler mode.","provenance":"source","from":"NVD"},"summary":{"text":"The flaw is an out-of-bounds write in Arm Trusted Firmware M (through version 1.2), affecting its handling of calls from the Non-Secure world into secure functions while the Non-Secure processing environment runs in handler mode. An attacker who can run code in the Non-Secure world with local access and low privileges can trigger a system halt, overwrite secure data, or cause secure data to be printed, with no user interaction required.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-10-23T07:14:32Z"},"cvss":{"score":5.5,"severity":"MEDIUM","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","provenance":"source","from":"NVD"},"epss":{"score":0.0306,"percentile":0.87572,"date":"2026-10-29","provenance":"source"},"kev":{"dateAdded":"2021-11-03","dueDate":"2021-11-17","ransomware":false,"requiredAction":"Apply updates per vendor instructions.","notes":"https://nvd.nist.gov/vuln/detail/CVE-2021-27562","provenance":"source"},"vulncheckKev":{"dateAdded":"2021-03-15","exploitedFirstSeen":"2021-03-15","ransomware":false,"evidence":[{"url":"https://unit42.paloaltonetworks.com/mirai-variant-iot-vulnerabilities/","date":"2021-03-15"},{"url":"https://www.fortinet.com/blog/threat-research/the-ghosts-of-mirai","date":"2021-06-24"},{"url":"https://www.radware.com/getmedia/18d24c2d-c092-4a61-9ad6-ebb92b7a49b8/Alert_Realtek_SDK.aspx","date":"2021-08-24"},{"url":"https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json","date":"2021-11-03"},{"url":"https://www.fortinet.com/blog/threat-research/Iz1h9-campaign-enhances-arsenal-with-scores-of-exploits","date":"2023-10-09"}],"evidenceTotal":5,"provenance":"source"},"exploited":true,"otx":{"pulseCount":50,"pulses":[{"name":"Actively_Exploited_Kev | Oct 29, 2026","url":"https://otx.alienvault.com/pulse/6ae20c1db17e7057ae7d9ad1","created":"2026-10-28"},{"name":"Actively_Exploited_Kev | Oct 28, 2026","url":"https://otx.alienvault.com/pulse/6ae0ba7e0e2a97ff7b218819","created":"2026-10-27"},{"name":"Actively_Exploited_Kev | Oct 27, 2026","url":"https://otx.alienvault.com/pulse/6adf68b85c3e852f3c111d18","created":"2026-10-26"},{"name":"Actively_Exploited_Kev | Oct 24, 2026","url":"https://otx.alienvault.com/pulse/6adb740e397c3ad4799aa4cd","created":"2026-10-23"},{"name":"Actively_Exploited_Kev | Oct 23, 2026","url":"https://otx.alienvault.com/pulse/6ada236fcfba2dfa730ea482","created":"2026-10-22"},{"name":"Actively_Exploited_Kev | Oct 22, 2026","url":"https://otx.alienvault.com/pulse/6ad8d33a077cbb5cab524d80","created":"2026-10-21"},{"name":"Actively_Exploited_Kev | Oct 21, 2026","url":"https://otx.alienvault.com/pulse/6ad78130c4d1ac2be83a8b6d","created":"2026-10-20"},{"name":"Actively_Exploited_Kev | Oct 20, 2026","url":"https://otx.alienvault.com/pulse/6ad62f63c24a405a3423cc13","created":"2026-10-19"},{"name":"Actively_Exploited_Kev | Oct 19, 2026","url":"https://otx.alienvault.com/pulse/6ad4dda174e5797d0bd238b7","created":"2026-10-18"},{"name":"Actively_Exploited_Kev | Oct 18, 2026","url":"https://otx.alienvault.com/pulse/6ad38c22e1848f8189d1c121","created":"2026-10-17"}],"provenance":"machine"},"cwes":[{"id":"CWE-787","name":"Out-of-bounds Write"}],"references":[{"url":"https://developer.arm.com/support/arm-security-updates","tags":["Vendor Advisory"]},{"url":"https://git.trustedfirmware.org/TF-M/trusted-firmware-m.git/tree/docs/security/security_advisories/svc_caller_sp_fetching_vulnerability.rst","tags":["Permissions Required","Third Party Advisory"]},{"url":"https://developer.arm.com/support/arm-security-updates","tags":["Vendor Advisory"]},{"url":"https://git.trustedfirmware.org/TF-M/trusted-firmware-m.git/tree/docs/security/security_advisories/svc_caller_sp_fetching_vulnerability.rst","tags":["Permissions Required","Third Party Advisory"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-27562","tags":["US Government Resource"]}],"techniques":[{"id":"T1068","name":"Exploitation for Privilege Escalation","tactics":["privilege-escalation"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: Non-secure world escalates into secure world privileges","mappingType":"exploitation_technique","evidence":[{"from":"description","quote":"the NS world may trigger a system halt, an overwrite of secure data","start":39,"end":106}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"},{"id":"T1499.004","name":"Application or System Exploitation","tactics":["impact"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: Triggered system halt causes application or system DoS","mappingType":"primary_impact","evidence":[{"from":"description","quote":"may trigger a system halt","start":52,"end":77}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"}],"reports":[],"affected":[],"advisories":[],"euvd":{"id":"EUVD-2021-14313","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2021-14313","exploited":true,"exploitedSince":"2021-11-03","provenance":"source"},"exploits":[],"exploitSources":null,"exploitRefs":[],"flow":[{"stage":"exploitation","techniques":["T1068"],"provenance":"ai"},{"stage":"primary","techniques":["T1499.004"],"provenance":"ai"}],"timeline":[{"date":"2021-03-15","kind":"exploited-reported","label":"Exploitation first reported (VulnCheck KEV evidence)","url":"https://unit42.paloaltonetworks.com/mirai-variant-iot-vulnerabilities/","provenance":"source"},{"date":"2021-05-25","kind":"published","label":"Published (NVD)","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-27562","provenance":"source"},{"date":"2021-11-03","kind":"kev","label":"Added to CISA KEV","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","provenance":"source"},{"date":"2021-11-03","kind":"euvd-exploited","label":"ENISA EUVD: exploited","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2021-14313","provenance":"source"}],"speed":{"daysToPublicExploit":null,"firstExploitFrom":null,"daysToKev":162},"priority":{"score":59.4,"factors":[{"name":"In a KEV catalog","points":35.0,"detail":"listed in CISA KEV and VulnCheck KEV"},{"name":"Recent KEV listing","points":0.0,"detail":"added 2054 days ago"},{"name":"Known ransomware use","points":0.0,"detail":"not known"},{"name":"EPSS percentile","points":17.51,"detail":"percentile 0.8757"},{"name":"Named in threat reports","points":0.0,"detail":"0 reports"},{"name":"Public exploit code","points":0.0,"detail":"none found"},{"name":"Mentioned in OTX pulses","points":3.0,"detail":"50 pulses"},{"name":"CVSS severity","points":3.85,"detail":"base score 5.5"},{"name":"End-of-life product","points":0.0,"detail":"supported or unknown"}]}}