CVE-2026-97078

Sprout Invoices – Client Invoicing & Estimates <= 20.8.17 - Unauthenticated Insecure Direct Object Reference

2026-09-24 00:00

Strategic Overview

Status: Patched in 20.8.18
Affected Plugin: Sprout Invoices – Client Invoicing & Estimates
Affected Version: <= 20.8.17
CVSS: 5.3Medium
Weakness type: CWE-639 · Authorization Bypass Through User-Controlled Key
CVE: CVE-2026-97078

View all Sprout Invoices – Client Invoicing & Estimates vulnerabilities

At a glance

CVE-2026-97078 is a medium-severity Authorization Bypass Through User-Controlled Key vulnerability in the Sprout Invoices WordPress plugin, affecting versions <= 20.8.17. It carries a CVSS score of 5.3 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 20.8.18; sites on affected versions should update now. Disclosed September 2026, reported by gueco.

Vulnerability Overview

The Sprout Invoices – Client Invoicing & Estimates plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 20.8.17. This is due to missing validation on a user controlled key. This makes it possible for unauthenticated attackers to perform an unauthorized action.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site, and no interaction from a victim user.

CWE-639: Authorization Bypass Through User-Controlled Key

Reaching this weakness in Sprout Invoices <= 20.8.17 takes no account at all. Authorization bypass through a user-controlled key, often called insecure direct object reference, means the application looks up a record by an identifier from the request without checking that the caller owns it.

Changing a number in the request is enough to read or modify other users' records, which on commerce and membership sites means customer data. For Sprout Invoices the fix is 20.8.18: builds <= 20.8.17 are affected, anything from 20.8.18 onward is not.

Remediation

Update to version 20.8.18, or a newer patched version

How does WordSec protect against this?

This one needs no account at all, which puts it outside what login hardening can reach; WordSec's login security narrows the account-level paths around it, and the firewall is what inspects the request itself. None of that substitutes for the fix: Sprout Invoices 20.8.18 closes this, and updating the plugin is the step that ends it.

Login Security
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2026-97078 https://www.wordfence.com/threat-intel/vulnerabilities/id/36dea43a-ec72-4425-8ebb-933c79c87290 https://nvd.nist.gov/vuln/detail/CVE-2026-97078

Related records

Same weakness class

Other vulnerabilities in Sprout Invoices – Client Invoicing & Estimates

CVSS Vector

5.3

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged
ConfidentialityNone
IntegrityLow
AvailabilityNone

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