NCSC-2026-0236

Vulnerability from csaf_ncscnl - Published: 2026-07-14 18:38 - Updated: 2026-07-14 18:38
Summary
Kwetsbaarheden verholpen in Microsoft Defender
Notes
The Netherlands Cyber Security Center (henceforth: NCSC-NL) maintains this page to enhance access to its information and security advisories. The use of this security advisory is subject to the following terms and conditions: NCSC-NL makes every reasonable effort to ensure that the content of this page is kept up to date, and that it is accurate and complete. Nevertheless, NCSC-NL cannot entirely rule out the possibility of errors, and therefore cannot give any warranty in respect of its completeness, accuracy or continuous keeping up-to-date. The information contained in this security advisory is intended solely for the purpose of providing general information to professional users. No rights can be derived from the information provided therein. NCSC-NL and the Kingdom of the Netherlands assume no legal liability or responsibility for any damage resulting from either the use or inability of use of this security advisory. This includes damage resulting from the inaccuracy of incompleteness of the information contained in the advisory. This security advisory is subject to Dutch law. All disputes related to or arising from the use of this advisory will be submitted to the competent court in The Hague. This choice of means also applies to the court in summary proceedings.
Feiten: Microsoft heeft kwetsbaarheden verholpen in Defender.
Interpretaties: Een kwaadwillende kan de kwetsbaarheden misbruiken om zich verhoogde rechten toe te kennen, willekeurige code uit te voeren met rechten van het systeem en/of toegang te krijgen tot gevoelige gegevens. De kwaadwillende moet het slachtoffer misleiden een malafide bestand te downloaden en openen.
Oplossingen: Microsoft heeft updates beschikbaar gesteld waarmee de beschreven kwetsbaarheden worden verholpen. We raden u aan om deze updates te installeren. Meer informatie over de kwetsbaarheden, de installatie van de updates en eventuele work-arounds vindt u op: https://portal.msrc.microsoft.com/en-us/security-guidance
Kans: medium
Schade: high
CWE-122: Heap-based Buffer Overflow
CWE-190: Integer Overflow or Wraparound
CWE-191: Integer Underflow (Wrap or Wraparound)
CWE-359: Exposure of Private Personal Information to an Unauthorized Actor
CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition
CVE-2026-55011

An integer underflow vulnerability in Microsoft Defender enables unauthorized local code execution due to wraparound behavior.

7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
CWE-191 - Integer Underflow (Wrap or Wraparound)
Affected products
Product Identifier Version Remediation
vers:unknown/*
Microsoft / Microsoft Defender for Endpoint for Mac
 vers:unknown/*
vers:unknown/*
Microsoft / Microsoft Malware Protection Engine
 vers:unknown/*
CVE-2026-55012

An integer overflow or wraparound vulnerability in Microsoft Defender enables an unauthorized attacker to execute code locally, posing a significant security risk.

7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CWE-122 - Heap-based Buffer Overflow
Affected products
Product Identifier Version Remediation
vers:unknown/*
Microsoft / Microsoft Defender for Endpoint for Mac
 vers:unknown/*
vers:unknown/*
Microsoft / Microsoft Malware Protection Engine
 vers:unknown/*
CVE-2026-50657

An exposure of private personal information vulnerability in Microsoft Defender allows an authorized local attacker to disclose sensitive data.

4.7 (Medium)
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C
CWE-359 - Exposure of Private Personal Information to an Unauthorized Actor
Affected products
Product Identifier Version Remediation
vers:unknown/*
Microsoft / Microsoft Defender for Endpoint for Mac
 vers:unknown/*
vers:unknown/*
Microsoft / Microsoft Malware Protection Engine
 vers:unknown/*
CVE-2026-50658

A time-of-check time-of-use (TOCTOU) race condition vulnerability in Microsoft Defender allows an authorized local attacker to elevate privileges.

7.0 (High)
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
CWE-367 - Time-of-check Time-of-use (TOCTOU) Race Condition
Affected products
Product Identifier Version Remediation
vers:unknown/*
Microsoft / Microsoft Defender for Endpoint for Mac
 vers:unknown/*
vers:unknown/*
Microsoft / Microsoft Malware Protection Engine
 vers:unknown/*
CVE-2026-56178

A time-of-check time-of-use (TOCTOU) race condition vulnerability in Microsoft Defender for Endpoint allows an authorized local attacker to elevate privileges.

5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N/E:U/RL:O/RC:C
CWE-367 - Time-of-check Time-of-use (TOCTOU) Race Condition
Affected products
Product Identifier Version Remediation
vers:unknown/*
Microsoft / Microsoft Defender for Endpoint for Mac
 vers:unknown/*
vers:unknown/*
Microsoft / Microsoft Malware Protection Engine
 vers:unknown/*
References
To clipboard 

{
  "document": {
    "category": "csaf_security_advisory",
    "csaf_version": "2.0",
    "distribution": {
      "tlp": {
        "label": "WHITE"
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    },
    "lang": "nl",
    "notes": [
      {
        "category": "legal_disclaimer",
        "text": "The Netherlands Cyber Security Center (henceforth: NCSC-NL) maintains this page to enhance access to its information and security advisories. The use of this security advisory is subject to the following terms and conditions:\n\n    NCSC-NL makes every reasonable effort to ensure that the content of this page is kept up to date, and that it is accurate and complete. Nevertheless, NCSC-NL cannot entirely rule out the possibility of errors, and therefore cannot give any warranty in respect of its completeness, accuracy or continuous keeping up-to-date. The information contained in this security advisory is intended solely for the purpose of providing general information to professional users. No rights can be derived from the information provided therein.\n\n    NCSC-NL and the Kingdom of the Netherlands assume no legal liability or responsibility for any damage resulting from either the use or inability of use of this security advisory. This includes damage resulting from the inaccuracy of incompleteness of the information contained in the advisory.\n    This security advisory is subject to Dutch law. All disputes related to or arising from the use of this advisory will be submitted to the competent court in The Hague. This choice of means also applies to the court in summary proceedings."
      },
      {
        "category": "description",
        "text": "Microsoft heeft kwetsbaarheden verholpen in Defender.",
        "title": "Feiten"
      },
      {
        "category": "description",
        "text": "Een kwaadwillende kan de kwetsbaarheden misbruiken om zich verhoogde rechten toe te kennen, willekeurige code uit te voeren met rechten van het systeem en/of toegang te krijgen tot gevoelige gegevens.\n\nDe kwaadwillende moet het slachtoffer misleiden een malafide bestand te downloaden en openen.",
        "title": "Interpretaties"
      },
      {
        "category": "description",
        "text": "Microsoft heeft updates beschikbaar gesteld waarmee de beschreven kwetsbaarheden worden verholpen. We raden u aan om deze updates te installeren. Meer informatie over de kwetsbaarheden, de installatie van de updates en eventuele work-arounds vindt u op:\n\nhttps://portal.msrc.microsoft.com/en-us/security-guidance",
        "title": "Oplossingen"
      },
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      {
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        "text": "Heap-based Buffer Overflow",
        "title": "CWE-122"
      },
      {
        "category": "general",
        "text": "Integer Overflow or Wraparound",
        "title": "CWE-190"
      },
      {
        "category": "general",
        "text": "Integer Underflow (Wrap or Wraparound)",
        "title": "CWE-191"
      },
      {
        "category": "general",
        "text": "Exposure of Private Personal Information to an Unauthorized Actor",
        "title": "CWE-359"
      },
      {
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        "text": "Time-of-check Time-of-use (TOCTOU) Race Condition",
        "title": "CWE-367"
      }
    ],
    "publisher": {
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      "name": "Nationaal Cyber Security Centrum",
      "namespace": "https://www.ncsc.nl/"
    },
    "title": "Kwetsbaarheden verholpen in Microsoft Defender",
    "tracking": {
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}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.