Unauthenticated self-registration in MailerUp allows access to stored email data

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Summary

CVECVE-2026-13164
StatePUBLISHED
AssignerSecur0
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-06-24 17:16:56 UTC
Updated2026-06-25 19:58:30 UTC
DescriptionMissing Authentication for Critical Function (CWE-306) in the RegisterView (apps/accounts/views.py), exposed at POST /api/auth/register/, in MailerUp <1.0.1 allows a remote, unauthenticated attacker to self-register a working account on instances where registration is intended to be restricted, because the endpoint applies the AllowAny permission with no email verification, CAPTCHA, or administrator approval. Any account created this way can read all email stored by the instance, resulting in full disclosure of stored messages to an arbitrary unauthenticated attacker

Risk And Classification

Primary CVSS: v4.0 8.8 HIGH from 4daa8cea-433a-44bd-9456-53b127fc289a

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS: 0.004060000 probability, percentile 0.323930000 (date 2026-06-29)

Problem Types: CWE-306 | CWE-306 CWE-306 Missing authentication for critical function

VersionSourceTypeScoreSeverityVector
4.04daa8cea-433a-44bd-9456-53b127fc289aSecondary8.8HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/C...
4.0CNACVSS8.8HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
None
Confidentiality
High
Integrity
Low
Availability
None
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Mailerup Mailerup affected 1.0.1 custom Not specified

References

ReferenceSourceLinkTags
github.com/Maalfer/mailerup/commit/99eb6d4586134bf3f4422093fbf47d6794ef0ee5 4daa8cea-433a-44bd-9456-53b127fc289a github.com
secur0.com/en/cna/cve-list/cve-2026-13164-unauthenticated-self-registrat... 4daa8cea-433a-44bd-9456-53b127fc289a secur0.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Dario Rivas Quero (en)

CNA: Cristian Fernandez Cornejo (en)

CNA: Mario Alvarez Fernandez (en)

CNA: Xoan M. Otero Jorge (en)

CNA: Secur0 CNA (en)

Additional Advisory Data

Solutions

CNA: Upgrade to version greater or equal than 1.0.1

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