CyberSecBulletin
CVE-2024-30040Exploited in the wildNVD status: Analyzed

Microsoft Windows MSHTML Platform Security Feature Bypass

Published Updated By the CyberSecBulletin desk

CVE-2024-30040 is a high-severity improper input validation vulnerability in Windows 10 Version 1809 from Microsoft, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. The record lists version 10.0.17763.5820 as the first without the flaw, so updating Windows 10 Version 1809 to that release or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on May 14, 2024, which means attacks have been observed in the wild.

Patch now

Attackers are already exploiting this vulnerability, according to CISA.

What to do

  1. Update Windows 10 Version 1809 to 10.0.17763.5820 or a later version.
  2. Update Windows Server 2019 to 10.0.17763.5820 or a later version.
  3. Update Windows Server 2019 (Server Core installation) to 10.0.17763.5820 or a later version.
  4. CISA's required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
  5. Read the advisory on msrc.microsoft.com for workarounds and exact fixed builds.
  6. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
  7. Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.

Affected products and versions

VendorProductAffected versionsFixed in
MicrosoftWindows 10 Version 180910.0.17763.0 up to, but not including, 10.0.17763.5820; 10.0.0 up to, but not including, 10.0.17763.582010.0.17763.5820
MicrosoftWindows Server 201910.0.17763.0 up to, but not including, 10.0.17763.582010.0.17763.5820
MicrosoftWindows Server 2019 (Server Core installation)10.0.17763.0 up to, but not including, 10.0.17763.582010.0.17763.5820
MicrosoftWindows Server 202210.0.20348.0 up to, but not including, 10.0.20348.246110.0.20348.2461
MicrosoftWindows 11 version 21H210.0.0 up to, but not including, 10.0.22000.296010.0.22000.2960
MicrosoftWindows 10 Version 21H210.0.19043.0 up to, but not including, 10.0.19044.441210.0.19044.4412
MicrosoftWindows 11 version 22H210.0.22621.0 up to, but not including, 10.0.22621.359310.0.22621.3593
MicrosoftWindows 10 Version 22H210.0.19045.0 up to, but not including, 10.0.19045.441210.0.19045.4412
MicrosoftWindows 11 version 22H310.0.22631.0 up to, but not including, 10.0.22631.359310.0.22631.3593
MicrosoftWindows 11 Version 23H210.0.22631.0 up to, but not including, 10.0.22631.359310.0.22631.3593
MicrosoftWindows Server 2022, 23H2 Edition (Server Core installation)10.0.25398.0 up to, but not including, 10.0.25398.88710.0.25398.887
MicrosoftWindows 10 Version 150710.0.10240.0 up to, but not including, 10.0.10240.2065110.0.10240.20651
MicrosoftWindows 10 Version 160710.0.14393.0 up to, but not including, 10.0.14393.698110.0.14393.6981
MicrosoftWindows Server 201610.0.14393.0 up to, but not including, 10.0.14393.698110.0.14393.6981
MicrosoftWindows Server 2016 (Server Core installation)10.0.14393.0 up to, but not including, 10.0.14393.698110.0.14393.6981
MicrosoftWindows 10 1507before 10.0.10240.2065110.0.10240.20651
MicrosoftWindows 10 1607before 10.0.14393.698110.0.14393.6981
MicrosoftWindows 10 1809before 10.0.17763.582010.0.17763.5820
MicrosoftWindows 10 21h2before 10.0.19044.441210.0.19044.4412
MicrosoftWindows 10 22h2before 10.0.19045.441210.0.19045.4412
MicrosoftWindows 11 21h2before 10.0.22000.296010.0.22000.2960
MicrosoftWindows 11 22h2before 10.0.22621.359310.0.22621.3593
MicrosoftWindows 11 23h2before 10.0.22631.359310.0.22631.3593
MicrosoftWindows Server 2022 23h2before 10.0.25398.88710.0.25398.887

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
RequiredA user must take an action such as opening a file or link.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. Scored by CNA (microsoft.com).

Scoring systemScoreSeverityScored by
CVSS 3.18.8HighCNA (microsoft.com)
CVSS 3.18.8HighCISA (ADP)

Official description

Windows MSHTML Platform Security Feature Bypass Vulnerability

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Input Validation

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

How developers prevent this class of flaw

  • Consider using language-theoretic security (LangSec) techniques that characterize inputs using a formal language and build recognizers for that language. This effectively requires parsing to be a distinct layer that effectively enforces a boundary between raw input and internal data representations, instead of allowing parser code to be scattered throughout the program, where it could be subject to errors or inconsistencies that create weaknesses.
  • Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
  • Understand all the potential areas where untrusted inputs can enter the product, including but not limited to: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls.

More Improper Input Validation vulnerabilities (CWE-20)

Timeline

  1. CVE record published.
  2. Added to CISA's Known Exploited Vulnerabilities catalogue.
  3. Deadline for US federal agencies to remediate, set by CISA.
  4. CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: total).
  5. Record last changed materially (score, affected products, status or references).

References

Third-party and government advisories

Recent Improper Input Validation vulnerabilities

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