Microsoft Internet Explorer Memory Corruption Vulnerability

Internet Explorer Memory Corruption Vulnerability

CheckOps priority index

9.0/10 Patch within 24 h

Severity8.8

Probability8.2

Exploitation5/5

Severity = CVSS. Probability = EPSS (FIRST). Exploitation = public signals: KEV, EUVD, ransomware, EPSS above 10 %, no account required.

EPSS · today 81.7% higher than 99.6% of CVEs

CVSS 3.1 8.8 AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:

Exploited for 1,826 days 03 Nov 2021

CISA due date 17 Nov 2021 for US federal agencies

Exploitation probability EPSS · FIRST

EPSS probability (%)Percentile among all CVEs

Exploitation signals 5 / 5

KEV catalog (CISA)03 Nov 2021
Exploited in EUVD (ENISA)03 Nov 2021
Used by ransomwareyes
EPSS above 10 %81.7%
No account, over the networkyes

What to do

Fix

Apply the vendor’s fix as soon as it is available.

CISA guidance: Apply updates per vendor instructions.

Meanwhile

Take the service off the internet or restrict access to it, watch the logs and look for signs of compromise.

Manufacturers (CRA)

Exploited vulnerability in your product: early warning to ENISA within 24 h, then notification within 72 h (Article 14 of the Cyber Resilience Act). The CRA explained

Affected products

Internet Explorer 9Microsoft Edge (EdgeHTML-based)Internet Explorer 11Internet Explorer

Affected versions

1.0.0 <6.0.6003.21070
1.0..0 <10.0.17134.2087
1.0.0 <10.0.17134.2087

Weaknesses (CWE)

CWE-416

Open source packages OSV

Affected libraries according to OSV, with fixed versions.

Timeline

11 Mar 2021
Published
03 Nov 2021
Exploitation reported (ENISA)
03 Nov 2021
Added to the KEV catalog
17 Nov 2021
CISA remediation due date
20 Oct 2026
EPSS peak: 81.7%

References

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