Google Chromium V8 Improper Input Validation Vulnerability
Google · Chromium V8
The flaw is an improper input validation issue in the V8 JavaScript engine of Google Chromium, which is the component shipped in Google Chrome. An attacker who can get a victim to load a crafted HTML page can potentially trigger heap corruption, requiring only remote network access, no authentication, and user interaction in the form of visiting that page.
Insufficient validation of untrusted input in V8 in Google Chrome prior to 89.0.4389.128 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.
- Exploited
- Yes, in CISA KEV
- Reports
- 0
- Tactics
- 2/15
How an attack unfolds
Based on MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. mappings. Select a step to see the evidence.Exploitation timelineDated milestones for a CVE: when it was disclosed, when exploit code became public, when exploitation was confirmed, and when threat reports named it.
First seen exploited 43 days after disclosure. Public exploit code (Metasploit) was available 13 days before disclosure.
- Public exploit codeMetasploit13 days before
- Disclosedday 0
- First seen exploitedVulnCheck KEV evidence+43 days
- Added to CISA KEVEU database agrees+6 mo
CISA KEV listing is when exploitation was confirmed, not necessarily the first attack.
MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. techniques
2 TechniqueOne specific attacker behaviour in MITRE ATT&CK, such as T1190 “Exploit Public-Facing Application”. IDs with a dot, like T1059.004, are sub-techniques., grouped by TacticThe attacker’s goal at a stage of an attack in MITRE ATT&CK, such as Initial Access or Persistence. Each technique belongs to one or more tactics. in kill-chain order, 2 cited passages 2Initial AccessTA0001
Malicious web page triggers browser exploit remotely
via a crafted HTML page
ExecutionTA0002
Heap corruption achieves code execution in browser process
allowed a remote attacker to potentially exploit heap corruption
Detection
0 rules for this CVE · 38 general rules for its techniquesRules for this CVE
0Sigma ruleAn open, vendor-neutral detection rule for log data. Security teams convert Sigma rules into searches for their own SIEM. that reference CVE-2021-21220 directly.CVE-specific rules are not available in this build. Search SigmaHQ ↗
General rules for this CVE’s techniques
These detect the technique in general, not this specific vulnerability.
Drive-by CompromiseT11893 general rules
Exploitation for Client ExecutionT120335 general rules
- Antivirus - Exploitation Framework Signaturecriticalstable
- Droppers Exploiting CVE-2017-11882criticalstable
- Audit CVE Eventcriticaltest
- CVE-2021-31979 CVE-2021-33771 Exploitscriticaltest
- CVE-2021-31979 CVE-2021-33771 Exploits by Sourgumcriticaltest
- Exploit for CVE-2017-8759criticaltest
- Antivirus - APT Malware Signaturecriticalexperimental
- Antivirus - Remote Access Tools Signaturecriticalexperimental
Sigma rules © SigmaHQ, Detection Rule License 1.1; linked, not reproduced.
What security researchers reported
Not named in any threat report yetAlso mentioned in 50 community threat pulses (AlienVault OTX)
Weaker evidencePulses are indicator collections that anyone can publish. A mention is not confirmation of exploitation.
- Actively_Exploited_Kev | Oct 29, 202628 Oct 2026
- Actively_Exploited_Kev | Oct 28, 202627 Oct 2026
- Actively_Exploited_Kev | Oct 27, 202626 Oct 2026
- Actively_Exploited_Kev | Oct 24, 202623 Oct 2026
- Actively_Exploited_Kev | Oct 23, 202622 Oct 2026
- Actively_Exploited_Kev | Oct 22, 202621 Oct 2026
- 44 more on OTX