CVE-2021-21086

HIGH

Adobe Acrobat and Reader DC < 20.013.20074 / < 17.011.30188 - Out-of-bounds Write in CoolType

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2021-21086. PoCs published by infobyte.

AI-analyzed exploit summary This repository contains a functional exploit for CVE-2021-21086, targeting Adobe Acrobat Reader DC 2020.013.20074 and earlier. The exploit leverages a Type 1 font charstring vulnerability to achieve remote code execution (RCE) by embedding a malicious charstring into a PDF file, which executes shellcode in the context of the rendering process.

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 an Out-of-bounds Write vulnerability in the CoolType library. 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.

Exploits (1)

nomisec WORKING POC 28 stars
by infobyte · poc
https://github.com/infobyte/Exploit-CVE-2021-21086

This repository contains a functional exploit for CVE-2021-21086, targeting Adobe Acrobat Reader DC 2020.013.20074 and earlier. The exploit leverages a Type 1 font charstring vulnerability to achieve remote code execution (RCE) by embedding a malicious charstring into a PDF file, which executes shellcode in the context of the rendering process.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Complex
Reliability
Reliable
Target: Adobe Acrobat Reader DC 2020.013.20074 and earlier
No auth needed
Prerequisites: Disable Adobe Reader's sandbox or use alternative shellcode · Python 3 environment with required dependencies (hexdump, colorama)
devstral-2 · analyzed Feb 18, 2026 Full analysis →

References (1)

Core 1
Core References

Scores

CVSS v3 7.8
EPSS 0.0464
EPSS Percentile 90.5%
Attack Vector LOCAL
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Details

CWE
CWE-787
Status published
Products (4)
adobe/acrobat 17.011.30056 - 17.011.30188
adobe/acrobat_dc 20.006.20042 - 20.013.20074
adobe/acrobat_reader 17.011.30059 - 17.011.30188
adobe/acrobat_reader_dc 20.006.20042 - 20.013.20074
Published Sep 02, 2021
Tracked Since Feb 18, 2026