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             AUSCERT External Security Bulletin Redistribution

     APSB21-104 Security update available for Adobe Acrobat and Reader
                              14 October 2021


        AusCERT Security Bulletin Summary

Product:           Acrobat DC
                   Acrobat Reader DC
                   Acrobat 2020
                   Acrobat Reader 2020
                   Acrobat 2017
                   Acrobat Reader 2017
Publisher:         Adobe
Operating System:  Windows
Impact/Access:     Execute Arbitrary Code/Commands -- Existing Account
                   Increased Privileges            -- Existing Account
Resolution:        Patch/Upgrade
CVE Names:         CVE-2021-40731 CVE-2021-40730 CVE-2021-40729

Original Bulletin: 

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Security update for Adobe Acrobat and Reader | APSB21-104

Bulletin ID                  Date Published                 Priority

APSB21-104               October 12, 2021                    2


Adobe has released security updates for Adobe Acrobat and Reader for Windows
and macOS. These updates address multiple critical and moderate 
vulnerabilities. Successful exploitation could lead to arbitrary code execution
in the context of the current user.

Affected Versions

Product           Track        Affected Versions                Platform

Acrobat DC         Continuous   21.007.20095 and earlier         Windows

                                21.007.20095 and earlier
Acrobat Reader DC  Continuous   versions                         Windows

Acrobat DC         Continuous   21.007.20096 and earlier         macOS

Acrobat Reader DC  Continuous   21.007.20096 and earlier         macOS

Acrobat 2020       Classic 2020 20.004.30015 and earlier         Windows &
                                versions                         macOS

Acrobat Reader     Classic 2020 20.004.30015 and earlier         Windows &
2020                            versions                         macOS

Acrobat 2017       Classic 2017 17.011.30202 and earlier         Windows &
                                versions                         macOS

Acrobat Reader     Classic 2017 17.011.30202 and earlier         Windows &
2017                            versions                         macOS

For questions regarding Acrobat DC, please visit the Acrobat DC FAQ page .

For questions regarding Acrobat Reader DC, please visit the Acrobat Reader DC
FAQ page .


Adobe recommends users update their software installations to the latest
versions by following the instructions below.

The latest product versions are available to end users via one of the following

  o Users can update their product installations manually by choosing Help >
    Check for Updates.

  o The products will update automatically, without requiring user
    intervention, when updates are detected.

  o The full Acrobat Reader installer can be downloaded from the Acrobat Reader
    Download Center .

For IT administrators (managed environments):

  o Refer to the specific release note version for links to installers.

  o Install updates via your preferred methodology, such as AIP-GPO,
    bootstrapper, SCUP/SCCM (Windows), or on macOS, Apple Remote Desktop and

Adobe categorizes these updates with the following priority ratings and
recommends users update their installation to the newest version:

Product        Track      Updated      Platform      Priority     Availability
                           Versions                   Rating

Acrobat DC      Continuous 21.007.20099 Windows and   2            Release
                                        macOS                      Notes

Acrobat Reader  Continuous 21.007.20099 Windows and   2            Release
DC                                      macOS                      Notes

Acrobat 2020    Classic    20.004.30017 Windows and   2            Release
                2020                    macOS                      Notes

Acrobat Reader  Classic    20.004.30017 Windows and   2            Release
2020            2020                    macOS                      Notes

Acrobat 2017    Classic    17.011.30204 Windows and   2            Release
                2017                    macOS                      Notes

Acrobat Reader  Classic    17.011.30204 Windows and   2            Release
2017            2017                    macOS                      Notes

Vulnerability Details

|             |Vulnerability|        |CVSS |               |                  |
|Vulnerability|   Impact    |Severity|base |  CVSS vector  |    CVE Number    |
|  Category   |             |        |score|               |                  |
|Use After    |Arbitrary    |        |     |CVSS:3.1/AV:L/ |                  |
|Free (       |code         |Critical|7.8  |AC:L/PR:N/UI:R/|CVE-2021-40728    |
|CWE-416 )    |execution    |        |     |S:U/C:H/I:H/A:H|                  |
|             |             |        |     |               |                  |
|Out-of-bounds|Privilege    |        |     |CVSS:3.1/AV:L/ |                  |
|Read (       |escalation   |Moderate|3.3  |AC:L/PR:N/UI:R/|CVE-2021-40729    |
|CWE-125 )    |             |        |     |S:U/C:L/I:N/A:N|                  |
|Use After    |Privilege    |        |     |CVSS:3.0/AV:L/ |                  |
|Free (       |escalation   |Moderate|3.3  |AC:L/PR:N/UI:R/|CVE-2021-40730    |
|CWE-416 )    |             |        |     |S:U/C:L/I:N/A:N|                  |
|Out-of-bounds|Arbitrary    |        |     |CVSS:3.0/AV:L/ |                  |
|Write (      |code         |Critical|7.8  |AC:L/PR:N/UI:R/|CVE-2021-40731    |
|CWE-787 )    |execution    |        |     |S:U/C:H/I:H/A:H|                  |


Adobe would like to thank the following for reporting these issues and for
working with Adobe to help protect our customers:

  o Habooblabs (CVE-2021-40728, CVE-2021-40729)
  o Kai Lu of Zscaler's ThreatLabz (CVE-2021-40729)
  o Anonymous working with Trend Micro Zero Day Initiative (CVE-2021-40730,


October 13th: Updated acknowledgements for CVE-2021-40729

For more information, visit https://helpx.adobe.com/security.html , or email

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