# CVE-2025-52691: SmarterTools SmarterMail Unrestricted Upload of File with Dangerous Type

> Unauthenticated attackers can upload arbitrary files to any location on SmarterMail, potentially enabling remote code execution.

- **Severity:** Critical 10.0 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Yes, since 26 Jan 2026 (CISA KEV), used in ransomware
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 29 Dec 2025
- **Updated:** 26 Feb 2026
- **Also known as:** GHSA-c9vj-8fwr-4gvq

## What is CVE-2025-52691?

CVE-2025-52691 is a critical vulnerability in SmarterTools SmarterMail, published on 29 Dec 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Successful exploitation of the vulnerability could allow an unauthenticated attacker to upload arbitrary files to any location on the mail server, potentially enabling remote code execution.

Weakness: CWE-434 (Unrestricted Upload of File with Dangerous Type)

## Which versions are affected by CVE-2025-52691?

It affects 1 product.


Products: Smartertools Smartermail.

## How do I fix CVE-2025-52691?

No fix has been published for CVE-2025-52691 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 16 Feb 2026.

## Is CVE-2025-52691 being exploited?

Yes. Attackers have exploited CVE-2025-52691 in the wild since at least 26 Jan 2026, including in ransomware campaigns.

Public exploit code:

- Detection for CVE-2025-52691 (github_poc): https://github.com/rxerium/CVE-2025-52691
- https://github.com/watchtowrlabs/watchTowr-vs-SmarterMail-CVE-2025-52691 (github_poc): https://github.com/watchtowrlabs/watchTowr-vs-SmarterMail-CVE-2025-52691
- An enhanced proof-of-concept exploit for CVE-2025-52691 (SmarterMail Arbitrary File Upload RCE) with APT-level features like stealth obfuscation, persistence, exfiltration, and interactive mode. For educational and authorized testing only. Credits to the original PoC by yt2w/CVE-2025-52691. (github_poc): https://github.com/DeathShotXD/CVE-2025-52691-APT-PoC
- https://github.com/rimbadirgantara/CVE-2025-52691-poc (github_poc): https://github.com/rimbadirgantara/CVE-2025-52691-poc
- This repository contains a safe Proof of Concept (PoC) to detect vulnerable SmarterMail versions affected by CVE‑2025‑52691.  The script performs version detection only and does not exploit the vulnerability. (github_poc): https://github.com/you-ssef9/CVE-2025-52691
- CVE-2025-52691 Scanner - Detects vulnerable SmarterMail installations (CVSS 10.0 RCE) (github_poc): https://github.com/nxgn-kd01/smartermail-cve-scanner

## Other vulnerabilities in SmarterTools SmarterMail

- [CVE-2026-24423](https://insights.sbomify.com/CVE-2026-24423/): SmarterTools SmarterMail Missing Authentication for Critical Function (critical 9.3, exploited in the wild)
- [CVE-2026-23760](https://insights.sbomify.com/CVE-2026-23760/): SmarterTools SmarterMail Authentication Bypass Using an Alternate Path or Channel (critical 9.3, exploited in the wild)
- [CVE-2021-32234](https://insights.sbomify.com/CVE-2021-32234/): Code injection in n/a (critical 9.8)
- [CVE-2019-7214](https://insights.sbomify.com/CVE-2019-7214/): Deserialization in n/a (critical 9.8)
- [CVE-2026-7807](https://insights.sbomify.com/CVE-2026-7807/): SmarterTools SmarterMail < Build 9560 Server Local File Inclusion via the /api/v1/report/summary/{type} API (high 8.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-52691 and fix it if it is affected.

What it is: CVE-2025-52691 is a critical vulnerability in SmarterTools SmarterMail, published on 29 Dec 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: Yes. Attackers have exploited CVE-2025-52691 in the wild since at least 26 Jan 2026, including in ransomware campaigns.

Affected product: SmarterTools SmarterMail. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-52691/ (Markdown: https://insights.sbomify.com/CVE-2025-52691/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-52691
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-52691
- OSV: https://osv.dev/vulnerability/CVE-2025-52691

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-52691/
Summaries are generated and may contain mistakes; the official description above is the record.