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CVE-2023-36884

From Exploited flaws, HARD’s guide to the flaws being used in attacks · Checked
This article is about a flaw in Microsoft Windows. For every flaw being used in attacks, see Exploited flaws; for Microsoft’s, see Microsoft flaws being used in attacks.

CVE-2023-36884 is a security flaw in Microsoft Windows, Microsoft’s operating system for PCs and servers. Opening a booby-trapped file can let an attacker run their own code through Microsoft Windows. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 17 Jul 2023, and says ransomware gangs have used it.[1]

Microsoft Windows is in things households have, such as phones, computers, browsers and everyday apps, so the fix matters at home as much as at work. Fixed in version 10.0.10240.20107, 10.0.14393.6167, 10.0.17763.4737 and 10.0.19044.3324 and others.

Description

CISA calls it a search remote code execution in Microsoft Windows. In its words: “Microsoft Windows Search contains an unspecified vulnerability that could allow an attacker to evade Mark of the Web (MOTW) defenses via a specially crafted malicious file, leading to remote code execution.”[1]

The underlying weakness is race condition (CWE-362), in MITRE’s list of common software weaknesses.[2]

It scores 7.5 out of 10 on the Common Vulnerability Scoring System, which rates it high, scored by the organisation that published the CVE using CVSS 3.1.[2]

Affected versions

NVD’s record lists these fixed versions: in each line, everything before the version shown is affected.[2]

ProductFixed in
Windows 10 Version 150710.0.10240.20107
Windows 10 Version 160710.0.14393.6167
Windows 10 Version 180910.0.17763.4737
Windows 10 Version 21H210.0.19044.3324
Windows 10 Version 22H210.0.19045.3324
Windows 11 version 21H210.0.22000.2295
Windows 11 version 22H210.0.22621.2134
Windows Server 2008 Service Pack 26.0.6003.22216

Every device with Microsoft Windows needs the update.

Exploitation

CISA added it to its catalog of known exploited vulnerabilities on 17 Jul 2023, 6 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 29 Aug 2023 to fix it.[1] CISA says ransomware gangs have used it.

FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at 99%. That’s in the top 1% of the flaws it scores.[4]

CISA assesses it as not automatable: each attack takes some work.

CISA doesn’t say who was attacked, or how.

Fix

Microsoft has published a fix or advice.[3] CISA’s required action: “Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.”[1]

  1. Update Microsoft Windows now.On Windows: Settings, Windows Update, Check for updates, then restart. Office updates come the same way, or from any Office app: File, Account, Update Options. Then turn on automatic updates, so the next fix arrives on its own.
  2. Check you’re on 10.0.10240.20107 or later.Fixed in version 10.0.10240.20107, 10.0.14393.6167, 10.0.17763.4737 and 10.0.19044.3324 and others. Anything older is what attackers are going after.
  3. If there’s no update, stop using it.CISA’s advice when a flaw being used in attacks has no fix is to stop using the product until it does.

Timeline

DateEvent
The flaw is made public in the National Vulnerability Database, with a severity score of 7.5.[2]
CISA adds it to its catalog of flaws known to be used in attacks, noting that ransomware gangs have used it.[1]
CISA’s deadline for US government agencies to fix it.[1]
FIRST puts the odds of it being used in attacks in the next 30 days at 99%.[4]

See also

Other Microsoft Windows flaws

Other race condition flaws

Every Microsoft flaw on CISA’s list · Everything added in July 2023

References

  1. ^ Cybersecurity and Infrastructure Security Agency. “Microsoft Windows Search Remote Code Execution Vulnerability”. Known Exploited Vulnerabilities Catalog, added 17 Jul 2023.
  2. ^ National Institute of Standards and Technology. “CVE-2023-36884 Detail”. National Vulnerability Database, published 11 Jul 2023.
  3. ^ Microsoft. Advisories and fixes: msrc.microsoft.com.
  4. ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.994, percentile 99.9, 31 Oct 2026.
  5. CVE Program. “CVE-2023-36884”. The official CVE record.

This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.