CVE-2021-21017 Adobe Acrobat and Reader: memory-safety flaw
In plain words: The program mishandles the memory it uses to keep track of data. A specially made input can scramble that memory. Usually lets an attacker crash the program or run their own code with its permissions.
Confirmed exploited by CISA on · US federal patch deadline Nov 17, 2021
What to do
- Install Adobe's security update for Acrobat and Reader. If no update exists, follow the vendor's workaround or stop using the product until one ships.
- Turn on automatic updates for the operating system and for Office, PDF and archive apps.
- Be careful with unexpected attachments — documents, .zip/.rar files and shortcuts are common bait.
- Use a normal (non-admin) account day to day and keep built-in protection like Microsoft Defender on.
Who is affected
Could reach you. This one is aimed at devices or apps of the kind people own.
What's at risk: Your files, saved passwords and accounts. Many of these let a program that is already running gain full administrator control.
The details
- Official name
- Adobe Acrobat and Reader Heap-based Buffer Overflow Vulnerability
- Product
- Adobe Acrobat and Reader
- CISA description
- Acrobat Acrobat and Reader contain a heap-based buffer overflow vulnerability that could allow an unauthenticated attacker to achieve code execution in the context of the current user.
- Type of flaw
- Memory-safety flaw (CWE-122)
- Confirmed exploited
- Nov 3, 2021
- US federal patch deadline
- Nov 17, 2021
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Answering about CVE-2021-21017 ·
Questions about CVE-2021-21017
Is CVE-2021-21017 being exploited?
Yes. CISA added CVE-2021-21017 to its Known Exploited Vulnerabilities catalog on Nov 3, 2021, which means there is reliable evidence of real-world attacks.
How do I fix CVE-2021-21017?
Install Adobe's security update for Acrobat and Reader. If no update exists, follow the vendor's workaround or stop using the product until one ships. Turn on automatic updates for the operating system and for Office, PDF and archive apps.
Am I affected by CVE-2021-21017?
Only if you use Adobe Acrobat and Reader. This one is aimed at devices or apps of the kind people own.