# CVE-2026-125749: TaxHacker through 0.8.5 IDOR via Settings Server Actions userId

Status: published. Published: 2026-11-10. Updated: 2026-11-10.

TaxHacker through 0.8.5 contains an insecure direct object reference vulnerability in app/(app)/settings/actions.ts that allows authenticated users to modify other users' data by supplying an arbitrary userId. Attackers can invoke Server Actions like deleteCategoryAction or editFieldAction with a victim's UUID to delete categories, clear transaction assignments, or alter LLM prompts.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/vas3k/TaxHacker/commit/d84a912f3a06b141cc275bb07115a204e7f10128

## Affected products and versions

- vas3k / TaxHacker (vas3k/TaxHacker): ≥ 0; ≤ 0.8.5 (affected, custom). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 2.3 (low); CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 4.2 (medium); CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:L; source: CNA: VulnCheck

- CVSS 4.0: 2.3 (low); CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X; source: NVD: disclosure@vulncheck.com

- CVSS 3.1: 4.2 (medium); CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:L; source: NVD: disclosure@vulncheck.com

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: exploitation poc; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-639

## Exploit evidence

- exploit: https://hackmd.io/@hieund/cve-2026-125749-taxhacker-settings-crud-actions-cross-user-authz (ADP: CISA-ADP)

## References

- https://github.com/vas3k/TaxHacker/issues/204 (CNA: VulnCheck; issue-tracking)

- https://github.com/vas3k/TaxHacker/commit/d84a912f3a06b141cc275bb07115a204e7f10128 (CNA: VulnCheck; patch)

- https://github.com/vas3k/TaxHacker/blob/v0.8.5/app/(app)/settings/actions.ts#L117-L306 (CNA: VulnCheck; technical-description)

- https://hackmd.io/@hieund/taxhacker-settings-crud-actions-cross-user-authz (CNA: VulnCheck; third-party-advisory)

- https://www.vulncheck.com/advisories/taxhacker-through-0.8.5-idor-via-settings-server-actions-userid (CNA: VulnCheck; third-party-advisory)

- https://hackmd.io/@hieund/cve-2026-125749-taxhacker-settings-crud-actions-cross-user-authz (ADP: CISA-ADP; exploit)

- https://github.com/vas3k/TaxHacker/blob/v0.8.5/app/(app)/settings/actions.ts#L117-L306 (disclosure@vulncheck.com)

- https://github.com/vas3k/TaxHacker/commit/d84a912f3a06b141cc275bb07115a204e7f10128 (disclosure@vulncheck.com)

- https://github.com/vas3k/TaxHacker/issues/204 (disclosure@vulncheck.com)

- https://hackmd.io/@hieund/taxhacker-settings-crud-actions-cross-user-authz (disclosure@vulncheck.com)

- https://www.vulncheck.com/advisories/taxhacker-through-0.8.5-idor-via-settings-server-actions-userid (disclosure@vulncheck.com)

- https://hackmd.io/@hieund/cve-2026-125749-taxhacker-settings-crud-actions-cross-user-authz (134c704f-9b21-4f2e-91b3-4a467353bcc0)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-125749; retrieved 2026-11-10; source updated 2026-11-10

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-125749; retrieved 2026-11-10; source updated 2026-11-10

Revision: 99f697dda50a00482edf18a954d865a5fc211f703be1d3eb0964c2550fe67b96

Canonical: https://y2.dev/cve/CVE-2026-125749

## Agent and API access

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- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

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