A remote code execution vulnerability exists in the way that the scripting engine handles objects in memory in Internet Explorer, aka 'Scri…

published 2019-11-12 6 y ago modified 2026-06-17 4 mo ago also EUVD-2019-9986

cvss: 7.5; version 3.1, CNA
cisa kev: Exploited; added 2021-11-03
epss: 77.3%; EPSS 77.3% chance of exploitation in 30 days, percentile 99.5%
public exploits: 1; Exploit-DB

A remote code execution vulnerability exists in the way that the scripting engine handles objects in memory in Internet Explorer, aka 'Scripting Engine Memory Corruption Vulnerability'. This CVE ID is unique from CVE-2019-1426, CVE-2019-1427, CVE-2019-1428.

Patch / fix

cisa required action Apply updates per vendor instructions.

links 1

portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-1429 advisory

Timeline

2019-11-12 0-day patched (Project Zero)
2019-11-12 Published
2019-11-22 First public exploit (EDB-47707)
2021-11-03 Added to CISA KEV
2022-05-03 CISA patch deadline
2025-02-07 CISA SSVC: exploitation active

Known exploited

Added: 5 y ago (2021-11-03)
Patch by: 2022-05-03 (4 y ago)
Ransomware: Not known
Required action: Apply updates per vendor instructions.
Vendor, product: Microsoft, Internet Explorer
CISA name: Microsoft Internet Explorer Scripting Engine Memory Corruption Vulnerability

Zero-day

Detected in real attacks while still unknown to the vendor and the public, per Google Project Zero's 0day In-the-Wild tracker.

Patched: 2019-11-12
Details: project zero root cause analysis

CISA SSVC

Exploitation: Active, exploited in the wild
Automatable: no
Technical impact: total
Assessed: 21 mo ago (2025-02-07)

Exploit prediction

77.29% chance of exploitation in the next 30 days, higher than 99.5% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

EDB-47707 Internet Explorer - Use-After-Free in JScript Arguments During toJSON Callback dos, 2019-11-22
packetstormsecurity.com http://packetstormsecurity.com/files/155433/Microsoft-Internet-Explorer-Use-After-Free.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CISA ADP	3.1	7.5	CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD	3.1	7.5	CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
CNA	3.1	7.5	CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD	2.0	7.6	AV:N/AC:H/Au:N/C:C/I:C/A:C

Affected products

Microsoft Internet Explorer 9
Microsoft Internet Explorer 11
Microsoft Internet Explorer 11 on Windows Server 2012
Microsoft Internet Explorer 11 on Windows 10 Version 1903 for 32-bit Systems
Microsoft Internet Explorer 11 on Windows 10 Version 1903 for x64-based Systems
Microsoft Internet Explorer 11 on Windows 10 Version 1903 for ARM64-based Systems
Microsoft Internet Explorer 10

Classification

Weakness

CWE-416 Use After Free
CWE-787 Out-of-bounds Write

References

portal.msrc.microsoft.com /en-US/security-guidance/advisory/CVE-2019-1429
patch, vendor-advisory
packetstormsecurity.com /files/155433/Microsoft-Internet-Explorer-Use-After-Free.html
exploit, third-party-advisory, vdb-entry
cisa.gov /known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-1429
government-resource, us-government-resource

Sources

CVE List CVE-2019-1429
NVD CVE-2019-1429

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary