CVE-2026-20838: Microsoft Windows 11 version 23H2 · Generation of Error Message Containing Sensitive Information
Affects Microsoft Windows 11 version 23H2Source CVE Database V5
Not known to be exploited · CVSS 5.5 Medium : upgrade to 10.0.22631.6491 when convenient.
Data as of 25 Oct 2026, 19:02 UTC
- EPSS
- 0.6% chance of exploitation in 30 days – higher than 50% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 10.0.22631.6491, 10.0.26100.7623, 10.0.26200.7623 +3
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:CExploitation evidence
Disclosed: evidence found.
CVE published 13 Jan 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| MicrosoftWindows 11 version 23H2 | Affected
| Fixed in
|
| MicrosoftWindows 11 Version 23H2 | Affected
| Fixed in
|
| MicrosoftWindows 11 Version 24H2 | Affected
| Fixed in
|
| MicrosoftWindows 11 Version 25H2 | Affected
| Fixed in
|
| MicrosoftWindows Server 2022 | Affected
| Fixed in
|
| MicrosoftWindows Server 2022, 23H2 Edition (Server Core installation) | Affected
| Fixed in
|
| MicrosoftWindows Server 2025 | Affected
| Fixed in
|
| MicrosoftWindows Server 2025 (Server Core installation) | Affected
| Fixed in
|
AI-suggested
An official fix is available from Microsoft. Users and administrators should apply the security update provided by Microsoft for Windows 11 version 23H2 to remediate this vulnerability. Refer to the Microsoft advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20838 for the update details and installation instructions.
Description
Generation of error message containing sensitive information in Windows Kernel allows an authorized attacker to disclose information locally.