CVE-2023-21823
CVE-2023-21823 is a security flaw in Microsoft Windows, Microsoft’s operating system for PCs and servers. Attackers can run their own code on Microsoft Windows. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 14 Feb 2023.[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 16.0.16130.20156, 2.70.23021003, 16.0.14326.21330 and 10.0.10240.19747 and others.
Description
CISA calls it a graphic component privilege escalation in Microsoft Windows. In its words: “Microsoft Windows Graphic Component contains an unspecified vulnerability that allows for privilege escalation.”[1]
The underlying weakness is integer overflow (CWE-190), in MITRE’s list of common software weaknesses.[2]
It scores 7.8 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]
| Product | Fixed in |
|---|---|
| Microsoft Office for Android | 16.0.16130.20156 |
| Microsoft Office for iOS | 2.70.23021003 |
| Microsoft Office for Universal | 16.0.14326.21330 |
| Windows 10 Version 1507 | 10.0.10240.19747 |
| Windows 10 Version 1607 | 10.0.14393.5717 |
| Windows 10 Version 1809 | 10.0.17763.4010 |
| Windows 10 Version 20H2 | 10.0.19042.2604 |
| Windows 10 Version 21H2 | 10.0.19044.2604 |
Every device with Microsoft Windows needs the update.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 14 Feb 2023, within a day of it being made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 7 Mar 2023 to fix it.[1]
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 6%. That’s in the top 8% 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 updates per vendor instructions.”[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.
- Check you’re on 16.0.16130.20156 or later.Fixed in version 16.0.16130.20156, 2.70.23021003, 16.0.14326.21330 and 10.0.10240.19747 and others. Anything older is what attackers are going after.
- 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
| Date | Event |
|---|---|
| The flaw is made public in the National Vulnerability Database, with a severity score of 7.8.[2] | |
| CISA adds it to its catalog of flaws known to be used in attacks.[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 6%.[4] |
See also
Other Microsoft Windows flaws
- CVE-2026-96951: command injection ·
- CVE-2026-85880: heap-based buffer overflow ·
- CVE-2026-81963: link following ·
- CVE-2008-4250: buffer overflow ·
- CVE-2026-32202: protection mechanism failure ·
- CVE-2025-60710: link following ·
Other integer overflow flaws
- CVE-2026-97229, GitLab Community Edition and Enterprise Edition: integer overflow or wraparound ·
- CVE-2025-48595, Android Framework: integer overflow ·
- CVE-2021-30952, Apple devices: integer overflow or wraparound ·
- CVE-2026-21385, Qualcomm Multiple Chipsets: memory corruption ·
- CVE-2018-14634, Linux Kernel: integer overflow ·
Added the same day
- CVE-2023-23529, Apple devices: webKit type confusion ·
- CVE-2023-23376, Microsoft Windows: common log file system (CLFS) driver privilege escalation ·
- CVE-2023-21715, Microsoft Office: publisher security feature bypass ·
Every Microsoft flaw on CISA’s list · Everything added in February 2023
References
- ^ Cybersecurity and Infrastructure Security Agency. “Microsoft Windows Graphic Component Privilege Escalation Vulnerability”. Known Exploited Vulnerabilities Catalog, added 14 Feb 2023.
- ^ National Institute of Standards and Technology. “CVE-2023-21823 Detail”. National Vulnerability Database, published 14 Feb 2023.
- ^ Microsoft. Advisories and fixes: msrc.microsoft.com, msrc.microsoft.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.056, percentile 92.9, 31 Oct 2026.
- CVE Program. “CVE-2023-21823”. 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.