CVE-2024-10635Network attack vector

Attachment scanning bypass via opaque S/MIME signature

Published Apr 28, 2025 · Updated Oct 6, 2025

Improper input validation in Proofpoint Enterprise Protection allows remote attackers to bypass attachment scanning with opaque S/MIME signatures. Attachment scanning fails to validate that an opaque-signed S/MIME attachment remains plaintext, so the message reaches the inbox without policy scanning. No authentication is required, but a recipient must open the delivered attachment for the downstream confidentiality and integrity impact.

CVSS severity6.1
Medium
EPSS probability0.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Proofpoint Enterprise Protection allows remote attackers to bypass attachment scanning with opaque S/MIME signatures. Attachment scanning fails to validate that an opaque-signed S/MIME attachment remains plaintext, so the message reaches the inbox without policy scanning. No authentication is required, but a recipient must open the delivered attachment for the downstream confidentiality and integrity impact.

The record

CVE
CVE-2024-10635
Published
Apr 28, 2025
Updated
Oct 6, 2025
Vendor
Proofpoint
Product
Proofpoint Enterprise Protection
Classifications
CWE-20, T1566.001, T1204.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 28, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 6, 2025Record 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=8.18.6 <patch 5110 changes=[{"at":"patch 4868","status":"unaffected"}]
  2. Affected versionversion=8.20.6 <patch 5134 changes=[{"at":"patch 4871","status":"unaffected"}]
  3. Affected versionversion=8.21.0 <patch 5112 changes=[{"at":"patch 4872","status":"unaffected"}]

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Proofpoint · Proofpoint Enterprise Protectionversion=8.18.6 <patch 5110 changes=[{"at":"patch 4868","status":"unaffected"}]; version=8.20.6 <patch 5134 changes=[{"at":"patch 4871","status":"unaffected"}]; version=8.21.0 <patch 5112 changes=[{"at":"patch 4872","status":"unaffected"}]

Published CVSS scores

5.3NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
6.1ProofpointCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/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.

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

CWE-20Improper Input Validation
T1566.001Spearphishing Attachment
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

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Your stack

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