InvoiceShelf: Authorization Bypass Through User-Controlled Key
CVE-2026-55610 is a high-severity authorization bypass through user-controlled key vulnerability in InvoiceShelf, with a CVSS 3.1 base score of 8.7 out of 10. It can be exploited remotely over the network by an attacker with administrator privileges, without any action from a user. Affected InvoiceShelf versions: < 2.4.1. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.43% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of InvoiceShelf you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| InvoiceShelf | InvoiceShelf | < 2.4.1 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- HighAdministrator-level access is required first.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N. Scored by CNA (github.com).
Official description
InvoiceShelf is an open-source web & mobile app that helps track expenses, payments and create professional invoices and estimates. Prior to version 2.4.1, in InvoiceShelf's multi-company installations, any user who is an Owner of one company can read and overwrite any user account in any other company on the same installation. `GET/PUT /api/v1/users/{user}` resolves the target `User` by global primary key, and `UserPolicy` checks only that the requester owns their own header-company — it never verifies that the target user belongs to that company. This allows cross-tenant disclosure of user data and full account takeover (email/password overwrite + company re-assignment). Version 2.4.1 fixes the issue.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Authorization Bypass Through User-Controlled Key
The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.
How developers prevent this class of flaw
- For each and every data access, ensure that the user has sufficient privilege to access the record that is being requested.
- Make sure that the key that is used in the lookup of a specific user's record is not controllable externally by the user or that any tampering can be detected.
- Use encryption in order to make it more difficult to guess other legitimate values of the key or associate a digital signature with the key so that the server can verify that there has been no tampering.
More Authorization Bypass Through User-Controlled Key vulnerabilities (CWE-639)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
References
Other vulnerabilities in InvoiceShelf
- 7.2 High severity
- 7.1 High severity
- 8.2 High severity
- 7.6 High severity
- 7.1 High severity
- 8.7 High severity
Recent Authorization Bypass Through User-Controlled Key vulnerabilities
- 8.2 High severity
- 7.3 High severity
- 9.1 Critical severity
- 8.8 High severity
- 7.1 High severity
- 7.1 High severity
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