CVE-2021-21017

Adobe Acrobat and Reader: Heap-based Buffer Overflow

As of , CVE-2021-21017 in Adobe Acrobat and Reader is on CISA's list of exploited vulnerabilities: CISA listed it on . Our patch-first group: Patch this week.

Exploited
Yes: CISA listed it on 3 November 2021
US federal deadline
17 November 202114 days after CISA listed it. US federal civilian agencies must fix it by then.
Used in ransomware campaigns
Not known to CISA
EPSS score
0.86Higher than 99% of the CVEs EPSS scores. EPSS estimates the chance of exploitation activity in the next 30 days.
EPSS when listed
Not availableCISA listed it before 4 February 2022, where the EPSS files we read begin.
Public exploit
None foundNeither Metasploit nor Exploit-DB lists one.
Fix
No vendor link in CISA's entry

What CISA says to do

Apply updates per vendor instructions.

CISA's required action

What the flaw is

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.

CISA's description

Acrobat Reader DC versions versions 2020.013.20074 (and earlier), 2020.001.30018 (and earlier) and 2017.011.30188 (and earlier) are affected by a heap-based buffer overflow vulnerability. An unauthenticated attacker could leverage this vulnerability to achieve arbitrary code execution in the context of the current user. Exploitation of this issue requires user interaction in that a victim must open a malicious file.

The CVE record's description, from adobe

CVE published
11 February 2021
Assigned by
adobe
CVSS
8.8 High (CVSS 3.1, from the CNA)
CWE-122
Heap-based Buffer Overflow
CISA SSVC, exploitation
active
CISA SSVC, automatable
no
CISA SSVC, technical impact
total

Timeline

  1. The CVE record was published.
  2. CISA added it to its list of exploited vulnerabilities.
  3. The US federal deadline to fix it.

Acrobat and Reader: other exploited entries

VulnerabilityProductOur groupListedDeadlineEPSS
CVE-2009-3459Heap-Based Buffer OverflowAdobe Acrobat and ReaderPatch this weekMetasploit module; EPSS 0.87; verified Exploit-DB entry0.87
CVE-2007-5659Buffer OverflowAdobe Acrobat and ReaderPatch this weekMetasploit module; EPSS 0.87; verified Exploit-DB entry0.87
CVE-2009-3953Universal 3D Remote Code ExecutionAdobe Acrobat and ReaderPatch this weekMetasploit module; EPSS 0.83; verified Exploit-DB entry0.83
CVE-2009-4324Use-After-FreeAdobe Acrobat and ReaderPatch this weekMetasploit module; EPSS 0.82; verified Exploit-DB entry0.82
CVE-2010-2883Stack-Based Buffer OverflowAdobe Acrobat and ReaderPatch this weekMetasploit module; EPSS 0.81; verified Exploit-DB entry0.81
CVE-2008-2992Reader and Acrobat Input ValidationAdobe Acrobat and ReaderPatch this weekRansomware use; Metasploit module; EPSS 0.98; verified Exploit-DB entry0.98
CVE-2023-21608Use-After-FreeAdobe Acrobat and ReaderPatch this weekEPSS 0.610.61
CVE-2021-28550Use-After-FreeAdobe Acrobat and ReaderPatch this weekEPSS 0.520.52
CVE-2008-0655UnspecifiedAdobe Acrobat and ReaderPatch soon0.38
CVE-2018-4990Double FreeAdobe Acrobat and ReaderPatch soon0.36

All 13 entries for Acrobat and Reader

Read further