# CVE-2026-27602: modoboa — Fixed in 2.7.1

🐍

🐍 PyPI

Not in CISA KEV

HIGH severity

# CVE-2026-27602 — modoboa

HIGH [Fix: modoboa/modoboa@27a7aa1](https://github.com/modoboa/modoboa/commit/27a7aa133d3608fe8c25ae39125d1012c333cbfa)

CVE-2026-27602 is a high-severity (CVSS 7.2) OS Command Injection vulnerability in modoboa. A fix is available for modoboa — see the affected versions and patch details below.

Modoboa has an OS Command Injection

Also known as[GHSA-wwv8-cqpr-vx3m](/vulnerability/GHSA-wwv8-cqpr-vx3m)PYSEC-2026-2223

Published

Mar 25, 2026

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

## Exploitation Status

### Proof-of-concept exploit code exists

-   CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
-   A successful exploit gives an attacker total control of the affected component, not partial access.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-27602.

## EPSS Exploitation Probability

[via FIRST.org ↗](https://www.first.org/epss/)

0.6%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs48th percentile — riskier than 48% of all scored CVEsHighest risk

0.00%0.40%0.79%1.19%0.1%0.6%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from [FIRST.org EPSS](https://www.first.org/epss/).

## How urgent is this, really

## Where this sits among everything scored

## Real-World Exposure

1 pkg affected

🐍`modoboa`

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

## Description

#### Summary

`exec_cmd()` in `modoboa/lib/sysutils.py` always runs subprocess calls with `shell=True`. Since domain names flow directly into shell command strings without any sanitization, a Reseller or SuperAdmin can include shell metacharacters in a domain name to run arbitrary OS commands on the server.

#### Details

The root cause is in `modoboa/lib/sysutils.py:31`:

```
kwargs["shell"] = True
process = subprocess.Popen(cmd, **kwargs)
```

When a create a domain is created with DKIM enabled, the domain name gets embedded into a shell command like this:

```
exec_cmd(f"openssl genrsa -out {dkim_storage_dir}/{domain.name}.pem {key_size}")
```

If the domain name contains something like `$(id>/tmp/proof).example.com`, the shell executes the injected command before running openssl.

The same pattern appears in several other places:

-   `modoboa/admin/jobs.py:38` — mailbox rename via `mv` using `full_address`
-   `modoboa/amavis/lib.py:202` — `sa-learn` using `domain.name`
-   `modoboa/admin/models/mailbox.py:150` — `doveadm user` using `full_address`
-   `modoboa/maillog/graphics.py:105–107` — `rrdtool` using `domain.name`
-   `modoboa/webmail/models.py:54–57` — `doveadm move/delete` using `account.email`

#### PoC

1.  Deploy modoboa <= 2.7.0
2.  Log in as a Reseller or SuperAdmin
3.  Create a new domain named `$(id>/tmp/proof).example.com` with DKIM enabled
4.  SSH into the server and read `/tmp/proof`

Something like this will be displayed:

```
uid=0(root) gid=0(root) groups=0(root)
```

Confirmed on commit b521bcb4f (latest main at time of discovery).

#### Impact

An attacker with Reseller-level access (or higher) can execute arbitrary OS commands on the mail server — in a typical Modoboa deployment this means running as root. All six identified sinks are reachable through normal application workflows.

## Affected Packages

1 total 1 fixed

Ecosystem

Package

Vulnerable range

Fix

🐍PyPI

`modoboa` 

all versions

2.7.1`pip install --upgrade 'modoboa==2.7.1'`

## Affected Products

1 product · 1 configurations

Application

`modoboa`modoboa

< 2.7.1

range

## Detection & mitigation playbook

Open-source dependency

1.  ### Detect
    
    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for modoboa, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
    
2.  ### Fix
    
    Update modoboa to 2.7.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-27602 is resolved across your whole dependency graph.
    
3.  ### Workarounds
    
    Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.
    

## Frequently Asked Questions

\### Summary \`exec\_cmd()\` in \`modoboa/lib/sysutils.py\` always runs subprocess calls with \`shell=True\`. Since domain names flow directly into shell command strings without any sanitization, a Reseller or SuperAdmin can include shell metacharacters in a domain name to run arbitrary OS commands on the server. ### Details The root cause is in \`modoboa/lib/sysutils.py:31\`: \`\`\`python kwargs\["shell"\] = True process = subprocess.Popen(cmd, \*\*kwargs) \`\`\` When a create a domain is created with DKIM enabled, the domain name gets embedded into a shell command like this: \`\`\`python exec\_cmd(f"openssl g

O3 Security · Impact-Aware SCA

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