CVE-2021-30610Network attack vector

Heap corruption via Extensions API use-after-free

Published Sep 3, 2021 · Updated Aug 3, 2024

Use-after-free in Microsoft Edge before 93.0.961.38 allows remote attackers to corrupt heap memory through a crafted HTML page. Public records identify the Extensions API as the affected component but do not disclose the freed object's lifetime error or a specific function. Exploitation requires a user to open attacker-controlled content; the documented consequence is browser-process heap corruption, without a public claim of sandbox escape or code execution.

CVSS severity8.8
High
EPSS probability4.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Microsoft Edge before 93.0.961.38 allows remote attackers to corrupt heap memory through a crafted HTML page. Public records identify the Extensions API as the affected component but do not disclose the freed object's lifetime error or a specific function. Exploitation requires a user to open attacker-controlled content; the documented consequence is browser-process heap corruption, without a public claim of sandbox escape or code execution.

The record

CVE
CVE-2021-30610
Published
Sep 3, 2021
Updated
Aug 3, 2024
Vendor
Microsoft
Product
Microsoft Edge (Chromium-based)
Classifications
CWE-416, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 3, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Microsoft · Microsoft Edge (Chromium-based)version=unspecified

Published CVSS scores

6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P
8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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