CVE-2021-35985

Application crash via PDFLibTool null dereference

Published Aug 20, 2021 · Updated Sep 16, 2024

Null pointer dereference in PDFLibTool in Adobe Acrobat Reader allows attackers to crash affected 2017, 2020, and DC releases via a malicious file. The affected tracks are 2021.005.20054 and earlier, 2020.004.30005 and earlier, and 2017.011.30197 and earlier; Adobe has not published deeper parsing details. Exploitation requires a victim to open the malicious file and only interrupts the Reader process running as the current user.

CVSS severity5.5
Medium
EPSS probability1.91%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Null pointer dereference in PDFLibTool in Adobe Acrobat Reader allows attackers to crash affected 2017, 2020, and DC releases via a malicious file. The affected tracks are 2021.005.20054 and earlier, 2020.004.30005 and earlier, and 2017.011.30197 and earlier; Adobe has not published deeper parsing details. Exploitation requires a victim to open the malicious file and only interrupts the Reader process running as the current user.

The record

CVE
CVE-2021-35985
Published
Aug 20, 2021
Updated
Sep 16, 2024
Vendor
Adobe
Product
Adobe Acrobat Reader
Classifications
CWE-476, T1204.002, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 20, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 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 <=2017.011.30197
  2. Affected versionversion=unspecified <=2020.004.30005
  3. Affected versionversion=unspecified <=2021.005.20054
  4. Affected versionversion=unspecified <=None

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Adobe · Adobe Acrobat Readerversion=unspecified <=2017.011.30197; version=unspecified <=2020.004.30005; version=unspecified <=2021.005.20054; version=unspecified <=None

Published CVSS scores

5.5AdobeCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1204.002User Execution: Malicious 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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