CVE-2021-26435: microsoft windows_10 Out-of-bounds Write
CVSS: 8.1v3.1HighModified
Published 15-09-2021Last modified 10-08-2026
Vulnerability summary
CVE-2021-26435 is a high (CVSS 8.1) Out-of-bounds Write vulnerability in microsoft windows_10. EPSS estimates a 5.38% chance of exploitation in the next 30 days, higher than 92.6% of scored vulnerabilities.
CVSS score
8.1/10
010
High · v3.1 (CVE.org)EPSS score
5.38%
0%100%
Low · +0.04 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Timeline
- 15-09-2021PublishedVulnerability first disclosed.
- 10-08-2026Last modifiedVulnerability information updated.
Description
Windows Scripting Engine Memory Corruption Vulnerability
CVSS metrics
3 scores · 2 sources · 2 versionsHigh 8.1Preferred score · CVE.org (CNA)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N/E:U/RL:O/RC:CSourcesAll 2 agree
- NVDNIST8.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
Medium 6.8Preferred score · NVD (NIST)
AV:N/AC:M/Au:N/C:P/I:P/A:PSourcesSingle source
EPSS trend
Probability
5.38%
Chance of exploitation in the next 30 days
Percentile
93%
Versus all other CVEs
30-day change
+0.04 pp
From 5.33% on 21-09-2026
21-09-202621-10-2026
EPSS score5.38%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Microsoft28 products
- windows_10na | 20h2 | 21h1 | 1607 | 1809 | 1909 | 2004
- windows 10 version 1507≥ 10.0.10240.0, < 10.0.10240.19060
- windows 10 version 1607≥ 10.0.14393.0, < 10.0.14393.4651
- windows 10 version 1809≥ 10.0.17763.0, < 10.0.17763.2183 | ≥ 10.0.0, < 10.0.17763.2183
- windows 10 version 1909≥ 10.0.0, < 10.0.18363.1801
1 vendor · 28 products
References
2 links
- portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26435X Refsource MISCX TransferredPatchVendor Advisory