CVE-2021-37984Network attack vector

Heap corruption via PDFium buffer overflow

Published Nov 2, 2021 · Updated Aug 4, 2024

A heap buffer overflow in PDFium in Google Chrome before 95.0.4638.54 allows remote attackers to corrupt heap memory via a crafted HTML page. Google has not published the affected function or the operation that exceeds the heap allocation. Reaching the flaw requires Chrome to render attacker-controlled page content, and public sources establish heap corruption but no narrower post-corruption result.

CVSS severity8.8
High
EPSS probability1.00%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A heap buffer overflow in PDFium in Google Chrome before 95.0.4638.54 allows remote attackers to corrupt heap memory via a crafted HTML page. Google has not published the affected function or the operation that exceeds the heap allocation. Reaching the flaw requires Chrome to render attacker-controlled page content, and public sources establish heap corruption but no narrower post-corruption result.

The record

CVE
CVE-2021-37984
Published
Nov 2, 2021
Updated
Aug 4, 2024
Vendor
Google Cloud
Product
Google Chrome
Classifications
CWE-787, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 2, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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 <95.0.4638.54

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Google Cloud · Google Chromeversion=unspecified <95.0.4638.54

Published CVSS scores

8.8NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
6.8NIST National Vulnerability DatabaseAV: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.

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-787Out-of-bounds Write
T1203Exploitation for Client Execution

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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