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NVD / CVE Program· CNA adobe

CVE-2021-39826: Adobe Digital Editions Command Execution Vulnerability

HighCVSS 8.6 · v3.1—No exploit No fix recorded

Noroxi assessment

Priority: Monitor (action score 35/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 2% (FIRST EPSS); higher than 81.6% of all records.
  • Someone with local access to the system can trigger it. No account or password is required. A user must open a link or visit a page. No special conditions are required; it is repeatable.
  • According to the record, no fixed version is available yet.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Update when a fix is released; follow the vendor's advisory.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

Published
Sep 27, 2021
Updated
Jun 17, 2026
EPSS
2.0% · 81th percentile

Report tools

JSON

Action score

35

Monitor

Low priority for now.

CVSS
34 / 40 · 8.6 / 10
CISA KEV
0 / 30 · Not listed
EPSS
1 / 30 · 2.0%

CNA vs NVD score

NVD
—
CNA · adobe
8.6
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • No fixed version yet

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2021-39826

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
adobedigital editions
applemacos

Versions reported by the vendor

Affected version ranges reported by the assigning authority (adobe). Independent of NVD's CPE analysis and usually ahead of it.

  • Adobe Digital Editions

    • unspecified and later · up to and including 4.5.11.187646affected
    • unspecified and later · up to and including Noneaffected

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • adobe digital editionsup to 4.5.11.187646 inclusive

Same product

adobe: all records

Other highest-scoring records for the same primary product.

  • CVE-2016-0954Adobe Digital Editions before 4.5.1 allows attackers to execute arbitrary code or cause a denial of service (memory corruption) via…
    44Plan
  • CVE-2019-7095Adobe Digital Editions versions 4.5.10.185749 and below have a heap overflow vulnerability.
    42Plan
  • CVE-2018-12814Adobe Digital Editions versions 4.5.8 and below have a heap overflow vulnerability.
    42Plan

Published before and after this one in the same product

  • ← EarlierCVE-2020-3798Jun 26, 2020 · Adobe Digital Editions versions 4.5.11.187212 and below have a file enumeration (host or local network) vulnerability.
    27Monitor
  • ← EarlierCVE-2021-21100Apr 15, 2021 · Adobe Digital Editions Arbitrary file system write vulnerability
    32Monitor
  • Later →CVE-2021-39827Sep 27, 2021 · Adobe Digital Editions Installer flaw leads to Arbitrary File System Write
    26Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • No account or password is required.
  • A user must open a link or visit a page.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted

Impact can extend beyond the vulnerable component (scope changes).

Attack vector
Local
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Changed
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-78 · Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

nvd-secondary

Root cause

User input is inserted as text into a shell command. The shell may interpret special characters in the input as part of the command.

The bug in code

The whole CWE-78 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
const host = req.body.host;exec("ping -c 1 " + host, onResult);

Fixed

ts
const host = req.body.host;if (!/^[a-z0-9.-]{1,253}$/i.test(host)) return res.sendStatus(400);execFile("ping", ["-c", "1", host], onResult);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records