CVE-2023-26421

Code execution via Doc object integer underflow

Published Apr 12, 2023 · Updated Mar 5, 2025

Integer underflow in Adobe Acrobat Reader allows remote attackers to execute code by getting a victim to open a malicious file. The Doc object handler inadequately validates user-supplied data, causing an integer underflow before a memory write and enabling code execution in the current process. Exploitation requires user interaction and affects Continuous 23.001.20093 and earlier and Classic 2020 20.005.30441 and earlier on Windows and macOS.

CVSS severity7.8
High
EPSS probability4.57%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Integer underflow in Adobe Acrobat Reader allows remote attackers to execute code by getting a victim to open a malicious file. The Doc object handler inadequately validates user-supplied data, causing an integer underflow before a memory write and enabling code execution in the current process. Exploitation requires user interaction and affects Continuous 23.001.20093 and earlier and Classic 2020 20.005.30441 and earlier on Windows and macOS.

The record

CVE
CVE-2023-26421
Published
Apr 12, 2023
Updated
Mar 5, 2025
Vendor
Adobe
Product
Adobe Acrobat Reader
Classifications
CWE-191, T1204.002, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 12, 2023CVE publishedPublication date reported by the CVE source.
  2. Mar 5, 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=unspecified <=20.005.30441
  2. Affected versionversion=unspecified <=23.001.20093
  3. Affected versionversion=unspecified <=None

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Adobe · Adobe Acrobat Readerversion=unspecified <=20.005.30441; version=unspecified <=23.001.20093; version=unspecified <=None

Published CVSS scores

7.8AdobeCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
7.8Zero Day InitiativeCVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-191Integer Underflow (Wrap or Wraparound)
T1204.002Malicious File
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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