CVE-2021-28558 | Adobe Acrobat Reader heap-based buffer overflow could lead to arbitrary code execution

Acrobat Reader DC versions versions 2021.001.20150 (and earlier), 2020.001.30020 (and earlier) and 2017.011.30194 (and earlier) are affected by an Heap-based buffer overflow vulnerability in the PDFLibTool component. 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.

Published: 2021-09-02 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-28558 is rated High Risk (67.4/100): CVSS High severity, with high exploitation likelihood (EPSS 41.54%, 97th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-28558

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-03-04 43.38% 41.54% -1.84%
2 2026-03-01 41.54% 43.38% +1.84%
3 2026-02-04 — 41.54% —

Full EPSS history (52 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-28558

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.8 3.0 HIGH
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 5.9 [email protected]
6.8 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.6 6.4 [email protected]

Weakness enumeration for CVE-2021-28558

Affected software / configurations for CVE-2021-28558

Vendor Product Version Raw CPE
adobe acrobat_dc >= 15.008.20082, <= 21.001.20150 cpe:2.3:a:adobe:acrobat_dc:*:*:*:*:continuous:*:*:*
adobe acrobat_reader_dc >= 15.008.20082, <= 21.001.20150 cpe:2.3:a:adobe:acrobat_reader_dc:*:*:*:*:continuous:*:*:*
adobe acrobat >= 17.011.30059, <= 17.011.30194 cpe:2.3:a:adobe:acrobat:*:*:*:*:classic:*:*:*
adobe acrobat >= 20.001.30005, <= 20.001.30020 cpe:2.3:a:adobe:acrobat:*:*:*:*:classic:*:*:*
adobe acrobat_reader >= 17.011.30059, <= 17.011.30194 cpe:2.3:a:adobe:acrobat_reader:*:*:*:*:classic:*:*:*
adobe acrobat_reader >= 20.001.30005, <= 20.001.30020 cpe:2.3:a:adobe:acrobat_reader:*:*:*:*:classic:*:*:*

References for CVE-2021-28558

cvelogic Threat Intelligence