CVE Vulnerabilities


Heap-based Buffer Overflow

Published: Aug 20, 2021 | Modified: Aug 31, 2021
CVSS 3.x
CVSS 2.x

Acrobat Reader DC versions 2021.005.20054 (and earlier), 2020.004.30005 (and earlier) and 2017.011.30197 (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.


A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().

Affected Software

Name Vendor Start Version End Version
Acrobat_dc Adobe 15.008.20082 (including) 21.005.20054 (including)
Acrobat_dc Adobe 17.011.30059 (including) 17.011.30197 (including)
Acrobat_dc Adobe 20.001.30005 (including) 20.004.30005 (including)
Acrobat_reader_dc Adobe 15.008.20082 (including) 21.005.20054 (including)
Acrobat_reader_dc Adobe 17.011.30059 (including) 17.011.30197 (including)
Acrobat_reader_dc Adobe 20.001.30005 (including) 20.004.30005 (including)

Potential Mitigations

  • Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking.
  • D3-SFCV (Stack Frame Canary Validation) from D3FEND [REF-1334] discusses canary-based detection in detail.
  • Run or compile the software using features or extensions that randomly arrange the positions of a program’s executable and libraries in memory. Because this makes the addresses unpredictable, it can prevent an attacker from reliably jumping to exploitable code.
  • Examples include Address Space Layout Randomization (ASLR) [REF-58] [REF-60] and Position-Independent Executables (PIE) [REF-64]. Imported modules may be similarly realigned if their default memory addresses conflict with other modules, in a process known as “rebasing” (for Windows) and “prelinking” (for Linux) [REF-1332] using randomly generated addresses. ASLR for libraries cannot be used in conjunction with prelink since it would require relocating the libraries at run-time, defeating the whole purpose of prelinking.
  • For more information on these techniques see D3-SAOR (Segment Address Offset Randomization) from D3FEND [REF-1335].