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High 8.8Known exploited (CISA KEV)Published Mar 11, 2021
CVE-2021-26411Internet Explorer Memory Corruption Vulnerability
Updated under an hour ago ()
Does this affect you?
It affects Microsoft Internet Explorer 11 and 4 other products. Add what you run to find out whether that includes you.
CISA lists it as known exploited since Nov 3, 2021; federal agencies had to remediate by Nov 17, 2021, and it is known to be used in ransomware. Treat that date as your deadline.
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Internet Explorer Memory Corruption Vulnerability
- CVSS
- 8.8 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:L/E:P/RL:O/RC:C
- Weakness (CWE)
- CWE-416
- Known exploited
- Added to CISA KEV Nov 3, 2021; federal remediation due Nov 17, 2021; known ransomware useApply updates per vendor instructions.
- EPSS (exploitation in the next 30 days)
- 80.77% (percentile 100)
- Assigned by
- microsoft
- NVD analysis
- Analyzed
- Record last updated
- Oct 1, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Microsoft Internet Explorer 11 microsoft:internet_explorer_11 (from the name) | from 1.0.0 before 10.0.17134.2087 | CNA record |
Microsoft Internet Explorer 9 microsoft:internet_explorer_9 (from the name) | from 1.0.0 before 6.0.6003.21070 | CNA record |
Microsoft Microsoft Edge (EdgeHTML-based) microsoft:edge_edgehtml_based (from the name) | from 1.0..0 before 10.0.17134.2087 | CNA record |
microsoft edge microsoft:edge | all versions | NVD |
microsoft internet_explorer microsoft:internet_explorer | 11; 9 | NVD |
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26411vendor-advisory, patch
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26411patch, vendor-advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26411us-government-resource
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.