CVE intelligence and bounded remediation

CVE-2021-39857 — Adobe Acrobat security vulnerability

Medium CVSS 4.3

Adobe Acrobat Reader DC add-on for Internet Explorer versions 2021.005.20060 (and earlier), 2020.004.30006 (and earlier) and 2017.011.30199 (and earlier) are affected by an Information Disclosure vulnerability. An unauthenticated attacker could leverage this vulnerability to check for existence of local files. Exploitation of this issue requires user interaction in that a victim must visit an attacker controlled web page.

Severity
Medium
CVSS
4.3 (3.0)
Published
2021-09-29
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-200

Affected products

  • adobe / acrobat
  • adobe / acrobat_reader
  • adobe / acrobat_dc
  • adobe / acrobat_reader_dc

Showing 4 representative product identities from 8 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Information disclosure and sensitive data exposure

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Trace sensitive data through responses, errors, logs, metrics, traces, caches, exports, files, backups, and client bundles.
  • Identify affected subjects, tenants, retention windows, access controls, and downstream copies without opening unnecessary sensitive records.
  • Review metadata, timing, status, length, and existence signals as well as direct content disclosure.

Remediate safely

  • Minimize collection and output, apply field-level authorization and redaction at a centralized boundary, and return generic external errors.
  • Remove secrets and sensitive data from logs, artifacts, URLs, caches, and client-side bundles; rotate credentials that may have been exposed.
  • Update the affected component and add synthetic-data tests for response, error, observability, and export paths.

Authoritative sources

Complete CVE record and remediation plan

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