CVE-2020-3804Public exploitNetwork attack vector

Information disclosure via malformed Unicode string parsing

Published Mar 25, 2020 · Updated Aug 4, 2024

Out-of-bounds read in Adobe Acrobat and Reader 2020.006.20034 and earlier allows attackers to disclose process memory via a crafted PDF. In EScript.api, Error.fileName construction passes a dynamically adjusted malformed Unicode string to strnlen_safe, which scans beyond its initialized heap buffer. Processing the crafted document can reveal adjacent memory, including addresses usable to bypass ASLR, but this flaw alone does not establish code execution.

CVSS severity7.5
High
EPSS probability3.46%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in Adobe Acrobat and Reader 2020.006.20034 and earlier allows attackers to disclose process memory via a crafted PDF. In EScript.api, Error.fileName construction passes a dynamically adjusted malformed Unicode string to strnlen_safe, which scans beyond its initialized heap buffer. Processing the crafted document can reveal adjacent memory, including addresses usable to bypass ASLR, but this flaw alone does not establish code execution.

The record

CVE
CVE-2020-3804
Published
Mar 25, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-125, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 25, 2020CVE 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.0NVDAV:N/AC:L/Au:N/C:P/I:N/A:N
7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1203Exploitation for Client Execution

Public exploit references

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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