How severe is CVE-2021-39843?

CVE-2021-39843 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-39843 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 76% (99th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-39843?

CVE-2021-39843 primarily affects Adobe Acrobat. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-39843?

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-2021-39843 published?

CVE-2021-39843 was published on 2021-09-29 and last updated on 2026-06-17.

CVE-2021-39843

CVE-2021-39843 is a high-severity vulnerability in Adobe Acrobat with a CVSS 3.x base score of 7.8. Its EPSS exploit-prediction score of 76% places it in the 99th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-787.

Key facts

Severity: High (CVSS 3.x base score 7.8)
CVSS v2: 6.8
EPSS exploit prediction: 76% (99th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Adobe Acrobat
Published: 2021-09-29
Last modified: 2026-06-17

Description

Acrobat Reader DC versions 2021.005.20060 (and earlier), 2020.004.30006 (and earlier) and 2017.011.30199 (and earlier) are affected by an out-of-bounds write vulnerability that could result in 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.

Frequently asked questions

What is CVE-2021-39843?: Acrobat Reader DC versions 2021.005.20060 (and earlier), 2020.004.30006 (and earlier) and 2017.011.30199 (and earlier) are affected by an out-of-bounds write vulnerability that could result in 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.
How severe is CVE-2021-39843?: CVE-2021-39843 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-39843 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 76% (99th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-39843?: CVE-2021-39843 primarily affects Adobe Acrobat. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-39843?: 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-2021-39843 published?: CVE-2021-39843 was published on 2021-09-29 and last updated on 2026-06-17.

References

https://helpx.adobe.com/security/products/acrobat/apsb21-55.html

Affected products (4)

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

More vulnerabilities in Adobe Acrobat

CVE-2018-4872 — Critical (CVSS 10.0): An issue was discovered in Adobe Acrobat Reader 2018.009.20050 and earlier versions, 2017.011.30070 and earlier…
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