CVE-2010-0806
CVE-2010-0806 is a security flaw in Microsoft Internet Explorer, Microsoft’s old web browser, still built into Windows. Attackers can run their own code on Microsoft Internet Explorer. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 20 May 2026.[1]
Microsoft Internet Explorer is in things households have, such as phones, computers, browsers and everyday apps, so the fix matters at home as much as at work. Microsoft has published a fix or advice.
Description
CISA calls it an use-after-free in Microsoft Internet Explorer. In its words: “Microsoft Internet Explorer contains an use-after-free vulnerability that could allow remote attackers to execute arbitrary code via vectors involving access to an invalid pointer after the deletion of an object. The impacted product could be end-of-life (EoL) and/or end-of-service (EoS). Users should discontinue product utilization.”[1]
The underlying weakness is CWE-399, in MITRE’s list of common software weaknesses.[2]
It scores 8.8 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 doesn’t list version ranges for it; Microsoft’s advisory has them[3]. CISA names the product as Microsoft Internet Explorer.
Every device with Microsoft Internet Explorer needs the update.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 20 May 2026, 5,915 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 3 Jun 2026 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 82%. 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, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.”[1]
- Update Microsoft Internet Explorer now.Install the latest update from Microsoft on every device that has it, and restart when asked. Then turn on automatic updates, so the next fix arrives on its own.
- 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 8.8.[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 82%.[4] |
See also
Other Microsoft Internet Explorer flaws
- CVE-2010-0249: use-after-free ·
- CVE-2010-3962: uninitialized memory corruption ·
- CVE-2013-3893: resource management errors ·
- CVE-2012-4792: use-after-free ·
- CVE-2013-3163: memory corruption ·
- CVE-2012-4969: use-after-free ·
Other Microsoft flaws
- CVE-2026-96951, Microsoft Windows: command injection ·
- CVE-2026-65660, Microsoft SharePoint: code injection ·
- CVE-2026-85880, Microsoft Windows: heap-based buffer overflow ·
- CVE-2026-81963, Microsoft Windows: link following ·
- CVE-2019-1068, Microsoft SQL Server: remote code execution ·
Similar flaws
- CVE-2014-0502, Adobe Flash Player: double free vulnerablity ·
- CVE-2009-4324, Adobe Acrobat and Reader: use-after-free ·
- CVE-2018-0180, Cisco IOS Software: denial-of-service ·
- CVE-2018-0179, Cisco IOS Software: denial-of-service ·
- CVE-2018-0161, Cisco IOS Software: resource management errors ·
Added the same day
- CVE-2026-45498, Microsoft Defender: denial of service ·
- CVE-2026-41091, Microsoft Defender: link following ·
- CVE-2010-0249, Microsoft Internet Explorer: use-after-free ·
- CVE-2009-3459, Adobe Acrobat and Reader: heap-based buffer overflow ·
- CVE-2009-1537, Microsoft DirectX: NULL byte overwrite ·
Every Microsoft flaw on CISA’s list · Everything added in May 2026
References
- ^ Cybersecurity and Infrastructure Security Agency. “Microsoft Internet Explorer Use-After-Free Vulnerability”. Known Exploited Vulnerabilities Catalog, added 20 May 2026.
- ^ National Institute of Standards and Technology. “CVE-2010-0806 Detail”. National Vulnerability Database, published 10 Mar 2010.
- ^ Microsoft. Advisories and fixes: learn.microsoft.com, docs.microsoft.com, learn.microsoft.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.822, percentile 99.7, 31 Oct 2026.
- CVE Program. “CVE-2010-0806”. 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.