CVE-2021-21218

Process-memory disclosure via uninitialized PDFium data

Published Apr 26, 2021 · Updated Aug 3, 2024

Uninitialized data exposure in PDFium in Google Chrome before 90.0.4430.72 allows remote attackers to read process memory via a crafted PDF. The public Chrome and CVE records do not identify the PDFium object left uninitialized or the code path that returns its bytes. Exploitation requires the affected browser to process the attacker-supplied PDF, and the reported consequence is limited to confidentiality.

CVSS severity5.5
Medium
EPSS probability1.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Uninitialized data exposure in PDFium in Google Chrome before 90.0.4430.72 allows remote attackers to read process memory via a crafted PDF. The public Chrome and CVE records do not identify the PDFium object left uninitialized or the code path that returns its bytes. Exploitation requires the affected browser to process the attacker-supplied PDF, and the reported consequence is limited to confidentiality.

The record

CVE
CVE-2021-21218
Published
Apr 26, 2021
Updated
Aug 3, 2024
Vendor
Google Cloud
Product
Google Chrome
Classifications
CWE-908, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 26, 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 <90.0.4430.72

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Google Cloud · Google Chromeversion=unspecified <90.0.4430.72

Published CVSS scores

4.3National Vulnerability DatabaseAV:N/AC:M/Au:N/C:P/I:N/A:N
5.5National Vulnerability DatabaseCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-908Use of Uninitialized Resource
T1204.002Malicious File

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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