{"cveID":"CVE-2021-21166","vendorProject":"Google","product":"Chromium","vulnerabilityName":"Google Chromium Race Condition Vulnerability","dateAdded":"2021-11-03","shortDescription":"Google Chromium contains a race condition vulnerability that allows a remote attacker to potentially exploit heap corruption via a crafted HTML page. This vulnerability could affect multiple web browsers that utilize Chromium, including, but not limited to, Google Chrome, Microsoft Edge, and Opera.","requiredAction":"Apply updates per vendor instructions.","dueDate":"2021-11-17","knownRansomwareCampaignUse":"Unknown","notes":"https://nvd.nist.gov/vuln/detail/CVE-2021-21166","cwes":["CWE-122","CWE-362"],"year":2021,"state":"mapped","stale_reasons":[],"mappings":[{"domain":"enterprise","cve":"CVE-2021-21166","technique":"T1059.007","technique_name_at_mapping":"JavaScript","mapping_type":"exploitation_technique","capability_group":"race_condition","comments":"CVE-2021-21166 allows an adversary to use JavaScript to exploit the Chromium browser via the audio object using a race condition to write into the heap. ","references":["https://googleprojectzero.github.io/0days-in-the-wild/0day-RCAs/2021/CVE-2021-21166.html"],"status":"complete","source_file":"kev-07.28.2025_attack-16.1-enterprise.json","attack_version":"16.1","kev_snapshot":"07/28/2025"},{"domain":"enterprise","cve":"CVE-2021-21166","technique":"T1203","technique_name_at_mapping":"Exploitation for Client Execution","mapping_type":"primary_impact","capability_group":"race_condition","comments":"CVE-2021-21166 allows an adversary to use JavaScript to exploit the Chromium browser via the audio object using a race condition to write into the heap. ","references":["https://googleprojectzero.github.io/0days-in-the-wild/0day-RCAs/2021/CVE-2021-21166.html"],"status":"complete","source_file":"kev-07.28.2025_attack-16.1-enterprise.json","attack_version":"16.1","kev_snapshot":"07/28/2025"}],"techniques":[{"id":"T1059.007","domains":["enterprise"],"in_current_bundle":true,"live":true,"name_now":"JavaScript","name_at_mapping":"JavaScript","renamed":false,"revoked_by":null,"mapping_types":["exploitation_technique"],"sigma_rule_count":29,"has_detection_strategy":true},{"id":"T1203","domains":["enterprise"],"in_current_bundle":true,"live":true,"name_now":"Exploitation for Client Execution","name_at_mapping":"Exploitation for Client Execution","renamed":false,"revoked_by":null,"mapping_types":["primary_impact"],"sigma_rule_count":35,"has_detection_strategy":true}],"mapping_types":["exploitation_technique","primary_impact"],"has_exploitation_technique":true,"mapping_attack_versions":["16.1"],"mapping_domains":["enterprise"],"sigma_coverage":"full","sigma_rules_tagged_cve":[],"added_after_mapping_snapshot":false,"_source":"kevmap","_built":"2026-08-23 05:47 UTC","_attack_version":"19.2"}