How severe is CVE-2021-39826?

CVE-2021-39826 has a CVSS 3.x base score of 8.6, 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-2021-39826 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-2021-39826?

CVE-2021-39826 affects Adobe Digital Editions. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-39826?

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-2021-39826 published?

CVE-2021-39826 was published on 2021-09-27 and last updated on 2026-06-17.

CVE-2021-39826

CVE-2021-39826 is a high-severity vulnerability in Adobe Digital Editions with a CVSS 3.x base score of 8.6. 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 8.6)
CVSS v2: 9.3
EPSS exploit prediction: 2% (80th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-78
Affected product: Adobe Digital Editions
Published: 2021-09-27
Last modified: 2026-06-17

Description

Adobe Digital Editions 4.5.11.187646 (and earlier) are affected by an arbitrary command execution vulnerability. An authenticated attacker could leverage this vulnerability to execute arbitrary commands. User interaction is required to abuse this vulnerability in that a user must open a maliciously crafted .epub file.

Frequently asked questions

What is CVE-2021-39826?: Adobe Digital Editions 4.5.11.187646 (and earlier) are affected by an arbitrary command execution vulnerability. An authenticated attacker could leverage this vulnerability to execute arbitrary commands. User interaction is required to abuse this vulnerability in that a user must open a maliciously crafted .epub file.
How severe is CVE-2021-39826?: CVE-2021-39826 has a CVSS 3.x base score of 8.6, 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-2021-39826 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-2021-39826?: CVE-2021-39826 affects Adobe Digital Editions. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-39826?: 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-2021-39826 published?: CVE-2021-39826 was published on 2021-09-27 and last updated on 2026-06-17.

References

https://helpx.adobe.com/security/products/Digital-Editions/apsb21-80.html

Affected products (1)

cpe:2.3:a:adobe:digital_editions:*:*:*:*:*:*:*:*

More vulnerabilities in Adobe Digital Editions

CVE-2017-3088 — Critical (CVSS 10.0): Adobe Digital Editions versions 4.5.4 and earlier have an exploitable memory corruption vulnerability in the PDF…
CVE-2014-0494 — Critical (CVSS 10.0): Adobe Digital Editions 2.0.1 allows attackers to execute arbitrary code or cause a denial of service (memory corruption…
CVE-2013-1377 — Critical (CVSS 10.0): Adobe Digital Editions 2.x before 2.0.1 allows attackers to execute arbitrary code or cause a denial of service (memory…
CVE-2020-3760 — Critical (CVSS 9.8): Adobe Digital Editions versions 4.5.10 and below have a command injection vulnerability. Successful exploitation could…
CVE-2019-7095 — Critical (CVSS 9.8): Adobe Digital Editions versions 4.5.10.185749 and below have a heap overflow vulnerability. Successful exploitation…
CVE-2018-12823 — Critical (CVSS 9.8): Adobe Digital Editions versions 4.5.8 and below have a heap overflow vulnerability. Successful exploitation could lead…

All CVEs affecting Adobe Digital Editions →

Other CWE-78 (OS Command Injection) vulnerabilities

CVE-2026-19188 — Critical (CVSS 10.0): A critical OS command injection vulnerability has been identified in the Haiwell IoT Cloud HMI Gateway product. The…
CVE-2026-48362 — Critical (CVSS 10.0): ColdFusion is affected by an Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')…
CVE-2026-16812 — Critical (CVSS 10.0): VeloCloud Orchestrator (VCO) on-prem has a security issue where this issue may allow a remote attacker to access…
CVE-2026-6516 — Critical (CVSS 10.0): Zohocorp ManageEngine ADAudit Plus versions before 8606 are affected by Unauthenticated Remote code execution due to…
CVE-2026-46339 — Critical (CVSS 10.0): 9Router is an AI router & token saver. From 0.4.30 until 0.4.37, 9Router's src/proxy.js middleware did not protect…
CVE-2026-59726 — Critical (CVSS 10.0): Ruflo is an agent meta-harness for Claude Code and Codex. Prior to 3.16.3, ruflo's default docker-compose deployment…

Browse all CWE-78 (OS Command Injection) vulnerabilities →