# CVE-2026-48824: axllent Mailpit memory exhaustion DoS in multiple API endpoints

Source: https://junglewise.ai/threats/cve-2026-48824-axllent-mailpit-memory-exhaustion-dos-in-multiple-api-endpoints  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-20. Updated: 2026-07-20  
License: CC BY 4.0 with a link back

CVE-2026-48824 · Severity: medium · CVSS 5.3 · Published 2026-07-20

Mailpit is a tool used by developers to test email functionality by capturing and viewing outgoing emails in a local environment. A security flaw allows an unauthenticated attacker to send specially crafted requests that consume excessive amounts of server memory. This can lead to the tool crashing or becoming unresponsive, disrupting development and testing workflows.

Technologies: [Axllent Mailpit](https://junglewise.ai/threats/technologies/mailpit), [github.com/axllent/mailpit (Go)](https://junglewise.ai/threats/technologies/github-com-axllent-mailpit). Vendors: [Axllent](https://junglewise.ai/threats/vendors/axllent), [Go](https://junglewise.ai/threats/vendors/go).

## Quick answers

**Is CVE-2026-48824 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-48824 being exploited in the wild.

**How severe is CVE-2026-48824?** Medium severity, with a CVSS score of 5.3, published 20 July 2026.

**Which products and versions are affected?** Axllent Mailpit <= 1.30.0, <= v1.30.0; github.com/axllent/mailpit (Go) <= 1.30.0, SEMVER:introduced=0,fixed=1.30.1.

**Is there a fix for CVE-2026-48824?** Yes. github.com/axllent/mailpit (Go): upgrade to 1.30.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-48824 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-48824?** Check whether you run Axllent Mailpit or github.com/axllent/mailpit (Go) 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/axllent/mailpit (Go): upgrade to 1.30.1 or later

  ```sh
  go get github.com/axllent/mailpit@v1.30.1
  ```


## Technical details

Mailpit fails to enforce request body size limits on four JSON API endpoints: PUT /api/v1/messages, DELETE /api/v1/messages, PUT /api/v1/tags, and POST /api/v1/message/{id}/release. While a previous fix (CVE-2026-45710) addressed this for the send endpoint using http.MaxBytesReader, these sibling endpoints still call json.NewDecoder(r.Body) directly. An unauthenticated attacker can provide a multi-million-element 'IDs' slice in a JSON body, causing significant memory amplification (approximately 28x the payload size) as the Go decoder materializes each element. This leads to Resident Set Size (RSS) growth that can trigger Out-Of-Memory (OOM) kills. The vulnerability is patched in version 1.30.1.

## Affected products

- axllent Mailpit <= 1.30.0

## Identifiers

- CVE-2026-48824
- GHSA-28pq-6qxg-wg5r
- GO-2026-5868

## Timeline

- 2026-05-28: patched: Version 1.30.1 released
- 2026-07-20: disclosed: CVE-2026-48824 published

## References

- [https://github.com/axllent/mailpit/releases/tag/v1.30.1](https://github.com/axllent/mailpit/releases/tag/v1.30.1)
- [https://github.com/axllent/mailpit/security/advisories/GHSA-28pq-6qxg-wg5r](https://github.com/axllent/mailpit/security/advisories/GHSA-28pq-6qxg-wg5r)

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