Microsoft Internet Explorer Use-After-Free
CVE-2010-0806 is a high-severity vulnerability in Internet Explorer from Microsoft, with a CVSS 2.0 base score of 9.3 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Internet Explorer versions: 5.01; 6; 8, and others listed below. The record does not name a fixed version, so check the vendor advisory. CISA added it to the Known Exploited Vulnerabilities catalogue on May 20, 2026, which means attacks have been observed in the wild.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Check which version of Internet Explorer you run against the affected versions below, and install the vendor's latest release.
- 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.
- Read the advisory on secunia.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Microsoft | Internet Explorer | 5.01; 6; 8; 7 | Not stated |
Version data comes from NVD's product matching. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Access vector
- NetworkCan be exploited remotely over a network.
- Access complexity
- MediumSome conditions must be met.
- Authentication
- NoneNo login is needed.
- Confidentiality
- CompleteAll data can be read.
- Integrity
- CompleteAny data can be modified.
- Availability
- CompleteThe system can be shut down completely.
Vector: AV:N/AC:M/Au:N/C:C/I:C/A:C. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.8 | High | CISA (ADP) |
| CVSS 2.0 | 9.3 | High | NVD |
Official description
Use-after-free vulnerability in the Peer Objects component (aka iepeers.dll) in Microsoft Internet Explorer 6, 6 SP1, and 7 allows remote attackers to execute arbitrary code via vectors involving access to an invalid pointer after the deletion of an object, as exploited in the wild in March 2010, aka "Uninitialized Memory Corruption Vulnerability."
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: total).
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- Deadline for US federal agencies to remediate, set by CISA.
- Record last changed materially (score, affected products, status or references).
References
Advisories
Patches and release notes
- kb.cert.org/vuls/id/744549US Government Resource
Third-party and government advisories
- us-cert.gov/cas/techalerts/TA10-068A.htmlUS Government Resource
- us-cert.gov/cas/techalerts/TA10-089A.htmlUS Government Resource
- exchange.xforce.ibmcloud.com/vulnerabilities/56772Third Party Advisory, VDB Entry
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2010-0806US Government Resource
Other vulnerabilities in Internet Explorer
- 8.8 High severity
- 8.8 High severity
- 7.5 High severity
- 8.8 High severity
- 7.5 High severity
- 7.5 High severity
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