Security readout for executives and security teams
Plain-English summary
ActualBudget Server versions before 26.2.1 may expose bank-sync data without login checks. If SimpleFIN or Pluggy.ai is configured and the server is reachable over a network, an unauthenticated person could read account balances and transaction history. This is a high-urgency privacy and financial-data exposure issue.
Executive priority
Treat as urgent for any network-reachable ActualBudget Server using SimpleFIN or Pluggy.ai. Prioritize patching because the exposed data is sensitive financial information and the attack conditions are simple. Systems without those integrations or not network-reachable have lower immediate exposure.
Technical view
CVE-2026-27584 is CWE-306 missing authentication in ActualBudget Server SimpleFIN and Pluggy.ai integration endpoints. Affected versions are actualbudget/actual before 26.2.1. The CVSS 4.0 score is 9.2, with network access, low complexity, no privileges, and no user interaction required. The vendor advisory states 26.2.1 patches the issue.
Likely exposure
Exposure is limited to ActualBudget Server instances before 26.2.1 that have SimpleFIN or Pluggy.ai integrations configured and are reachable over the network. Internet-exposed or broadly reachable self-hosted instances are the highest concern.
Exploitation context
The provided sources do not state active exploitation, and the CVE is not marked KEV. The issue is still serious because it requires no authentication or user interaction and can disclose sensitive financial balances and transaction history when the vulnerable integration endpoints are reachable.
Researcher notes
The public record attributes the flaw to missing authentication middleware on SimpleFIN and Pluggy.ai bank-sync endpoints. The bundled references identify the fixing version and commit. Do not assume impact for other integrations without vendor evidence. No public source in the bundle confirms exploitation in the wild.
Mitigation direction
- Upgrade ActualBudget Server to version 26.2.1 or later.
- Restrict network access to ActualBudget Server until upgraded.
- Review vendor advisory for any additional guidance.
- Disable SimpleFIN or Pluggy.ai integrations if upgrade cannot be completed promptly.
Validation and detection
- Inventory ActualBudget Server instances and record versions.
- Confirm whether SimpleFIN or Pluggy.ai integrations are configured.
- Determine whether the server is reachable from untrusted networks.
- Verify upgrade to ActualBudget Server 26.2.1 or later.
- Review access logs for unusual unauthenticated requests to bank-sync endpoints.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-306: Credential and account abuse lookup
Authentication and credential weaknesses can make valid-account abuse and credential telemetry useful review starting points. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2026-27584 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.2 (4.0)
- Known Exploited
- No
- Published
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N——Primary CVE scoreVulnerability scoring details
Base CVSS 4.0 score
9.2CriticalVector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/actualbudget/actual/security/advisories/GHSA-m2cq-xjgm-f668CVE reference · x_refsource_CONFIRM
- https://github.com/actualbudget/actual/commit/ea937d100956ca56689ff852d99c28589e2a7d88CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Missing Authentication for Critical Function
Missing Authentication for Critical Function represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.