CVE-2026-27584

HighPublic PoC

Published: 24 February 2026

Published

24 February 2026

Modified

26 February 2026

KEV Added

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Patch

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CVSS Score 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS Score 0.0017 37.9th percentile

Risk Priority 15 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-27584 is a high-severity Missing Authentication for Critical Function (CWE-306) vulnerability in Actualbudget Actual. Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 37.9th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

This vulnerability is AI-related — categorised as Other AI Platforms.

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploit Public-Facing Application (T1190).

Threat & Defense Details

Likely Mitigating ControlsAI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

AC-11 Device Lock

addresses: CWE-306

Requires established identification and authentication to unlock, mitigating missing authentication for continued system access.

AC-14 Permitted Actions Without Identification or Authentication

addresses: CWE-306

Requiring identification and rationale for actions allowed without authentication ensures critical functions are not left unprotected by forcing review of authentication requirements.

AC-19 Access Control for Mobile Devices

addresses: CWE-306

Authorizing mobile device connections to organizational systems ensures authentication is performed for this critical access function.

AC-25 Reference Monitor

addresses: CWE-306

Guarantees critical functions are protected by mandatory invocation of the access control mechanism.

AU-14 Session Audit

addresses: CWE-306

Auditing sessions makes it possible to detect access to critical functions without required authentication.

CA-2 Control Assessments

addresses: CWE-306

The assessment process confirms authentication is present and effective for critical functions, preventing exploitation from missing authentication.

CA-4 Security Certification

addresses: CWE-306

Certification assesses that critical functions have required authentication controls in place.

CM-7 Least Functionality

addresses: CWE-306

Disabling non-essential functions and services eliminates the need to secure them, reducing exposure from missing authentication on unnecessary components.

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

attack.mitre.org →

Why these techniques?

Missing authentication on network-exposed integration endpoints of a public-facing server directly enables unauthenticated remote access to sensitive data, matching T1190 Exploit Public-Facing Application.

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1

NVD Description

Actual is a local-first personal finance tool. Prior to version 26.2.1, missing authentication middleware in the ActualBudget server component allows any unauthenticated user to query the SimpleFIN and Pluggy.ai integration endpoints and read sensitive bank account balance and transaction information.…

This vulnerability allows an unauthenticated attacker to read the bank account balance and transaction history of ActualBudget users. This vulnerability impacts all ActualBudget Server users with the SimpleFIN or Pluggy.ai integrations configured. The ActualBudget Server instance must be reachable over the network. Version 26.2.1 patches the issue.

Deeper analysisAI

CVE-2026-27584 is a missing authentication vulnerability (CWE-306) in the ActualBudget server component of Actual, a local-first personal finance tool. In versions prior to 26.2.1, the server lacks authentication middleware for the SimpleFIN and Pluggy.ai integration endpoints, allowing unauthenticated users to query these endpoints and access sensitive bank account balance and transaction information. The vulnerability, published on 2026-02-24 with a CVSS v3.1 score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N), impacts all ActualBudget Server users who have configured SimpleFIN or Pluggy.ai integrations and expose the server over the network.

An unauthenticated attacker with network access to the ActualBudget Server can exploit this vulnerability by directly querying the affected integration endpoints. Successful exploitation enables the attacker to read the bank account balances and full transaction histories of affected ActualBudget users, resulting in high confidentiality impact without requiring privileges, user interaction, or system disruption.

Version 26.2.1 of Actual patches the issue by adding the necessary authentication middleware. Security practitioners should review the GitHub security advisory at https://github.com/actualbudget/actual/security/advisories/GHSA-m2cq-xjgm-f668 and the patching commit at https://github.com/actualbudget/actual/commit/ea937d100956ca56689ff852d99c28589e2a7d88 for implementation details and upgrade guidance.