How severe is CVE-2021-28634?

CVE-2021-28634 has a CVSS 3.x base score of 8.2, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-28634 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (80th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-28634?

CVE-2021-28634 primarily affects Adobe Acrobat Dc. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-28634?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-28634 published?

CVE-2021-28634 was published on 2021-08-20 and last updated on 2026-06-17.

CVE-2021-28634

CVE-2021-28634 is a high-severity vulnerability in Adobe Acrobat Dc with a CVSS 3.x base score of 8.2. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-78.

Key facts

Severity: High (CVSS 3.x base score 8.2)
CVSS v2: 8.5
EPSS exploit prediction: 2% (80th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-78
Affected product: Adobe Acrobat Dc
Published: 2021-08-20
Last modified: 2026-06-17

Description

Acrobat Reader DC versions 2021.005.20054 (and earlier), 2020.004.30005 (and earlier) and 2017.011.30197 (and earlier) are affected by an Improper Neutralization of Special Elements used in an OS Command. An authenticated attacker could leverage this vulnerability to achieve arbitrary code execution on the host machine in the context of the current user. Exploitation of this issue requires user interaction in that a victim must open a malicious file.

Frequently asked questions

What is CVE-2021-28634?: Acrobat Reader DC versions 2021.005.20054 (and earlier), 2020.004.30005 (and earlier) and 2017.011.30197 (and earlier) are affected by an Improper Neutralization of Special Elements used in an OS Command. An authenticated attacker could leverage this vulnerability to achieve arbitrary code execution on the host machine in the context of the current user. Exploitation of this issue requires user interaction in that a victim must open a malicious file.
How severe is CVE-2021-28634?: CVE-2021-28634 has a CVSS 3.x base score of 8.2, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-28634 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (80th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-28634?: CVE-2021-28634 primarily affects Adobe Acrobat Dc. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-28634?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-28634 published?: CVE-2021-28634 was published on 2021-08-20 and last updated on 2026-06-17.

References

https://helpx.adobe.com/security/products/acrobat/apsb21-51.html

Affected products (4)

cpe:2.3:a:adobe:acrobat_dc:*:*:*:*:continuous:*:*:*
cpe:2.3:a:adobe:acrobat_dc:*:*:*:*:classic:*:*:*
cpe:2.3:a:adobe:acrobat_reader_dc:*:*:*:*:continuous:*:*:*
cpe:2.3:a:adobe:acrobat_reader_dc:*:*:*:*:classic:*:*:*

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