CVE-2021-39827

Arbitrary file write via insecure temporary directory

Published Sep 27, 2021 · Updated Sep 17, 2024

Arbitrary file write in Adobe Digital Editions 4.5.11.187646 and earlier allows local users to write files during macOS installation. The installer creates a temporary file in a directory with permissions that allow another authenticated local user to modify its contents; Adobe discloses no finer code-level locus. Exploitation requires high-privileged local access and user interaction before installation, and the result is an arbitrary filesystem write.

CVSS severity6.5
Medium
EPSS probability1.50%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Arbitrary file write in Adobe Digital Editions 4.5.11.187646 and earlier allows local users to write files during macOS installation. The installer creates a temporary file in a directory with permissions that allow another authenticated local user to modify its contents; Adobe discloses no finer code-level locus. Exploitation requires high-privileged local access and user interaction before installation, and the result is an arbitrary filesystem write.

The record

CVE
CVE-2021-39827
Published
Sep 27, 2021
Updated
Sep 17, 2024
Vendor
Adobe
Product
Adobe Digital Editions
Classifications
CWE-379
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Sep 27, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <=4.5.11.187646
  2. Affected versionversion=unspecified <=None

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Adobe · Adobe Digital Editionsversion=unspecified <=4.5.11.187646; version=unspecified <=None

Published CVSS scores

6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P
6.5AdobeCVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-379Creation of Temporary File in Directory with Insecure Permissions

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo