CVE-2021-30611Network attack vector

Heap corruption via WebRTC use-after-free

Published Sep 3, 2021 · Updated Aug 3, 2024

Use-after-free in Microsoft Edge's WebRTC component allows remote attackers to trigger heap corruption through crafted HTML. Public records identify WebRTC as the affected locus but do not disclose the freed object's lifetime error, responsible function, or unsafe dereference. Exploitation requires user interaction and, according to the earlier NVD description, installation of a malicious extension before the crafted page is processed.

CVSS severity8.8
High
EPSS probability2.80%
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's WebRTC component allows remote attackers to trigger heap corruption through crafted HTML. Public records identify WebRTC as the affected locus but do not disclose the freed object's lifetime error, responsible function, or unsafe dereference. Exploitation requires user interaction and, according to the earlier NVD description, installation of a malicious extension before the crafted page is processed.

The record

CVE
CVE-2021-30611
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

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

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 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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