CVE-2021-33795

Signature misattribution via reversed certificate-name ordering

Published Jul 9, 2021 · Updated Aug 3, 2024

Signature-verification errors in Foxit Reader and PhantomPDF before 10.1.4 allow attackers to misattribute invisible PDF signatures. The signature display reads certificate names in the wrong order and labels the document owner as the signature author. A user must inspect an invisible digital signature in a crafted PDF, enabling false attribution of the signer without reported code execution or data disclosure.

CVSS severity5.5
Medium
EPSS probability0.77%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Signature-verification errors in Foxit Reader and PhantomPDF before 10.1.4 allow attackers to misattribute invisible PDF signatures. The signature display reads certificate names in the wrong order and labels the document owner as the signature author. A user must inspect an invisible digital signature in a crafted PDF, enabling false attribution of the signer without reported code execution or data disclosure.

The record

CVE
CVE-2021-33795
Published
Jul 9, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-755, T1036
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 9, 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

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:P/A:N
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

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.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-755Improper Handling of Exceptional Conditions
T1036Masquerading

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

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Your stack

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