CVE-2026-55610Public exploitNetwork attack vector

Cross-tenant account takeover via unscoped user lookup

Published Sep 23, 2026 · Updated Sep 23, 2026

Authorization bypass in InvoiceShelf 2.4.0 and earlier allows remote authenticated users to take over accounts across companies. GET and PUT /api/v1/users/{user} bind a globally keyed User, while UserPolicy tests only ownership of the requester's header company and never the target's membership. A company Owner can read another tenant's user data, overwrite email and password, and reassign the victim as a super administrator.

CVSS severity8.7
High
EPSS probability0.30%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authorization bypass in InvoiceShelf 2.4.0 and earlier allows remote authenticated users to take over accounts across companies. GET and PUT /api/v1/users/{user} bind a globally keyed User, while UserPolicy tests only ownership of the requester's header company and never the target's membership. A company Owner can read another tenant's user data, overwrite email and password, and reassign the victim as a super administrator.

The record

CVE
CVE-2026-55610
Published
Sep 23, 2026
Updated
Sep 23, 2026
Vendor
InvoiceShelf
Product
InvoiceShelf
Classifications
CWE-639, T1098
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Sep 23, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 23, 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=< 2.4.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

InvoiceShelf · InvoiceShelfversion=< 2.4.1

Published CVSS scores

8.7GitHubCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/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.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesadmin
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-639Authorization Bypass Through User-Controlled Key
T1098Account Manipulation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

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