CVE-2010-3971

Status: ModifiedHigh (9.3)—💥 Exploit

Use-after-free vulnerability in the CSharedStyleSheet::Notify function in the Cascading Style Sheets (CSS) parser in mshtml.dll, as used in Microsoft Internet Explorer 6 through 8 and other products, allows remote attackers to execute arbitrary code or cause a denial of service (application crash) via a self-referential @import rule in a stylesheet, aka "CSS Memory Corruption Vulnerability."

CVSS

Version: 2.0
Vector: AV:N/AC:M/Au:N/C:C/I:C/A:C
Base score: 9.3

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 82%
Percentile among all scored CVEs: 100
Score date: 10/7/2026

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

💥 Public exploits

Exploit code or detection templates are publicly available. This is not the same as confirmed active exploitation (KEV), but it raises the risk: patch with priority.

Metasploit module (reliable, widely available exploit) · MS11-003 Microsoft Internet Explorer CSS Recursive Import Use After Free
Published on Exploit-DB · Microsoft Internet Explorer - CSS Recursive Import Use-After-Free (MS11-003) (Metasploit) (2/8/2011)
Published on Exploit-DB · Microsoft Internet Explorer 8 - CSS Parser (12/15/2010)
Published on Exploit-DB · Microsoft Internet Explorer 8 - CSS Parser Denial of Service (12/8/2010)
Proof of concept on GitHub (unverified) · List of proofs of concept on GitHub

⚠️ GitHub proofs of concept are not verified: some are fake or contain malware. Never run them outside an isolated lab.

Affected technologies (1)

Microsoft — Internet Explorer

CWEs

CWE-399

References

Raw JSON (NVD)

Show

{
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      "value": "Use-after-free vulnerability in the CSharedStyleSheet::Notify function in the Cascading Style Sheets (CSS) parser in mshtml.dll, as used in Microsoft Internet Explorer 6 through 8 and other products, allows remote attackers to execute arbitrary code or cause a denial of service (application crash) via a self-referential @import rule in a stylesheet, aka \"CSS Memory Corruption Vulnerability.\""
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