CVE-2026-29133Network attack vector

Identity spoofing via mismatched PGP key UIDs

Published Apr 2, 2026 · Updated Apr 2, 2026

Improper input validation in SEPPmail Secure Email Gateway before 15.0.3 allows remote authenticated users to upload PGP keys with mismatched UIDs. The PGP-key upload path accepts a key when its UID does not match the uploader's email address, binding identity metadata without enforcing that relationship. An authenticated gateway account and a crafted key are required; the mismatch enables a key to be presented under an email identity it does not own.

CVSS severity5.3
Medium
EPSS probability0.23%
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 SEPPmail Secure Email Gateway before 15.0.3 allows remote authenticated users to upload PGP keys with mismatched UIDs. The PGP-key upload path accepts a key when its UID does not match the uploader's email address, binding identity metadata without enforcing that relationship. An authenticated gateway account and a crafted key are required; the mismatch enables a key to be presented under an email identity it does not own.

The record

CVE
CVE-2026-29133
Published
Apr 2, 2026
Updated
Apr 2, 2026
Vendor
SEPPmail
Product
Secure Email Gateway
Classifications
CWE-20, CAPEC-194, T1036
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 2, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 2, 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 <15.0.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

SEPPmail · Secure Email Gatewayversion=0 <15.0.3

Published CVSS scores

9.1NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
5.3NCSC.chCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA: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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
CAPEC-194Fake the Source of Data
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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