CVE-2021-33794Network attack vector

Information disclosure or crash via invalid form data

Published Aug 11, 2021 · Updated Aug 3, 2024

Uninitialized-variable handling in Foxit Reader and PhantomPDF before 10.1.4 allows attackers to disclose data or crash via an XFA form. During XFA form interaction, discrepant form-control data causes an array access violation when Tab focuses a field and new text is entered. A crafted PDF and form interaction are required; exploitation exposes process memory or terminates the desktop application.

CVSS severity9.1
Critical
EPSS probability1.10%
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

Uninitialized-variable handling in Foxit Reader and PhantomPDF before 10.1.4 allows attackers to disclose data or crash via an XFA form. During XFA form interaction, discrepant form-control data causes an array access violation when Tab focuses a field and new text is entered. A crafted PDF and form interaction are required; exploitation exposes process memory or terminates the desktop application.

The record

CVE
CVE-2021-33794
Published
Aug 11, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1204.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 11, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
6.4NIST NVDAV:N/AC:L/Au:N/C:P/I:N/A:P

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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1204.002Malicious File

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