SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityAnalyzed

CVE-2021-21017

Adobe Acrobat and Reader Heap-based Buffer Overflow Vulnerability

KEVHIGH 8.8EPSS 86.3%

Does this matter?

Known to be exploited in the wild (CISA KEV, CISA remediation deadline 17 November 2021). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.

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.

CVSS 3.1
8.8 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS
86.33% probability · 100th percentile
CISA KEV
Listed 3 November 2021 · due 17 November 2021
Weakness
CWE-122, CWE-787
Affected
adobe/acrobat · adobe/acrobat dc · adobe/acrobat reader · adobe/acrobat reader dc
Source
psirt@adobe.com

CISA notes

Apply updates per vendor instructions. https://nvd.nist.gov/vuln/detail/CVE-2021-21017

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.