# CVE-2026-39901: monetr improper authorization in transaction update endpoint

Source: https://junglewise.ai/threats/cve-2026-39901-monetr-improper-authorization-in-transaction-update-endpoint  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-04-08. Updated: 2026-07-24  
License: CC BY 4.0 with a link back

CVE-2026-39901 · Severity: medium · CVSS 5.7 · Published 2026-04-08

monetr is a budgeting application used to track and plan recurring expenses. A flaw in the software allows users to bypass restrictions and hide or 'soft-delete' imported financial transactions that are supposed to be permanent. This can lead to inaccurate financial records, compromised bookkeeping integrity, and the loss of a reliable audit trail for synced expenses.

Technologies: [github.com/monetr/monetr (Go)](https://junglewise.ai/threats/technologies/github-com-monetr-monetr). Vendors: [Go](https://junglewise.ai/threats/vendors/go).

## Quick answers

**Is CVE-2026-39901 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-39901 being exploited in the wild.

**How severe is CVE-2026-39901?** Medium severity, with a CVSS score of 5.7, published 8 April 2026.

**Which products and versions are affected?** github.com/monetr/monetr (Go) <= 1.12.2, SEMVER:introduced=0,fixed=1.12.3; Monetr < 1.12.3, <= 1.12.2.

**Is there a fix for CVE-2026-39901?** Yes. github.com/monetr/monetr (Go): upgrade to 1.12.3 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-39901 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-39901?** Check whether you run github.com/monetr/monetr (Go) or Monetr at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- github.com/monetr/monetr (Go): upgrade to 1.12.3 or later

  ```sh
  go get github.com/monetr/monetr@v1.12.3
  ```


## Technical details

The vulnerability is an improper authorization and integrity flaw (CWE-285) within the transaction update (PUT) path. While the application correctly blocks the deletion of synced transactions via the dedicated DELETE handler, the PUT endpoint fails to filter server-managed fields. An authenticated attacker can submit a full Transaction object containing a user-supplied 'deletedAt' value. The server persists this field, effectively soft-deleting the record and hiding it from standard views. This bypasses the immutability policy intended for imported transaction records. The issue is resolved in version 1.12.3.

## Affected products

- monetr monetr < 1.12.3

## Identifiers

- CVE-2026-39901
- GHSA-hqxq-hwqf-wg83
- GO-2026-5434

## Timeline

- 2026-04-07: advisory: GitHub Security Advisory published
- 2026-04-08: disclosed: CVE-2026-39901 published
- 2026-04-08: patched: Fix released in version 1.12.3

## References

- [https://github.com/monetr/monetr/security/advisories/GHSA-hqxq-hwqf-wg83](https://github.com/monetr/monetr/security/advisories/GHSA-hqxq-hwqf-wg83)

## Related threats

- [monetr SSRF in Lunch Flow integration](https://junglewise.ai/threats/cve-2026-41644-monetr-ssrf-in-lunch-flow-integration)
- [In monetr, unauthenticated Stripe webhook reads attacker-sized request bodies before signature validation](https://junglewise.ai/threats/cve-2026-40481-in-monetr-unauthenticated-stripe-webhook-reads-attacker-sized)