CVE-2026-27221

Signer-identity spoofing via improper signature verification

Published Mar 10, 2026 · Updated Mar 10, 2026

Improper signature verification in Adobe Acrobat Reader 25.001.21265 and earlier allows attackers to spoof a PDF signer’s identity. The digital-signature validation path fails to verify signer identity correctly; Adobe has not disclosed the precise failed check or certificate condition. Exploitation requires user interaction, and the reported result is false signer attribution rather than code execution or service interruption.

CVSS severity5.5
Medium
EPSS probability0.10%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper signature verification in Adobe Acrobat Reader 25.001.21265 and earlier allows attackers to spoof a PDF signer’s identity. The digital-signature validation path fails to verify signer identity correctly; Adobe has not disclosed the precise failed check or certificate condition. Exploitation requires user interaction, and the reported result is false signer attribution rather than code execution or service interruption.

The record

CVE
CVE-2026-27221
Published
Mar 10, 2026
Updated
Mar 10, 2026
Vendor
Adobe
Product
Adobe Acrobat Reader
Classifications
CWE-347, CWE-295, T1036
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 10, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 10, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=0 <=25.001.21265

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Adobe · Adobe Acrobat Readerversion=0 <=25.001.21265

Published CVSS scores

5.5AdobeCVSS: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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-347Improper Verification of Cryptographic Signature
CWE-295Improper Certificate Validation
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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