CVE-2024-21326Network attack vector

Sandbox escape via use-after-free memory access

Published Jan 26, 2024 · Updated Jun 17, 2025

Use-after-free in Microsoft Edge (Chromium-based) before 121.0.2277.83 allows remote attackers to escape the browser sandbox via crafted web content. Microsoft has not disclosed the affected Edge component or the object-lifetime sequence that permits access after memory is freed. Exploitation requires a user to open attacker-controlled content, after which the attacker gains privileges outside the browser sandbox.

CVSS severity9.6
Critical
EPSS probability1.23%
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 (Chromium-based) before 121.0.2277.83 allows remote attackers to escape the browser sandbox via crafted web content. Microsoft has not disclosed the affected Edge component or the object-lifetime sequence that permits access after memory is freed. Exploitation requires a user to open attacker-controlled content, after which the attacker gains privileges outside the browser sandbox.

The record

CVE
CVE-2024-21326
Published
Jan 26, 2024
Updated
Jun 17, 2025
Vendor
Microsoft
Product
Microsoft Edge (Chromium-based)
Classifications
CWE-416, T1203, T1068
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 26, 2024CVE publishedPublication date reported by the CVE source.
  2. Jun 17, 2025Record 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=1.0.0 <121.0.2277.83

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Microsoft · Microsoft Edge (Chromium-based)version=1.0.0 <121.0.2277.83

Published CVSS scores

8.3Microsoft CorporationCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C
9.6Microsoft CorporationCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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