CVE-2026-40187 egroupware vulnerability
In egroupware version 26.0 and earlier, an authenticated administrator can achieve OS-level Remote Code Execution (RCE) by uploading a malicious eTemplate XML file (`.xet`) to the VFS `/etemplates` mount. The `Widget::expand_name()` method passes template widget attribute values directly into a PHP `eval()` call with only double-quote escaping applied - **backtick characters are not escaped**. In PHP, backticks inside a double-quoted `eval()` string execute shell commands. This allows an admin-level user to escalate from web application access to arbitrary OS command execution on the server.
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EGroupware should be reviewed and updated if it matches the affected versions. The recommended fix is to apply the vendor-supported patched version or the mitigation steps below, then retest the public website with Fixnx.
Who is affected
Affected versions
- <= 26.0
Fixed versions
- Apply the latest vendor-supported patched version.
How to fix it
CVE-2026-40187 affects EGroupware and involves code or command execution. Successful exploitation may let an attacker run unintended code or operating-system commands in the affected process. Prioritize internet-facing, privileged, automation, and production deployments. No confirmed fixed version is recorded for CVE-2026-40187; follow the linked vendor advisory, apply its mitigation, and update EGroupware as soon as a supported patched release is available.
- Inventory every deployment, device, package, plugin, container, build, and environment that uses EGroupware.
- Compare the installed version with the recorded affected range: <= 26.0.
- No confirmed fixed version is recorded for CVE-2026-40187; follow the linked vendor advisory, apply its mitigation, and update EGroupware as soon as a supported patched release is available.
- Until patched, disable the affected feature, limit untrusted input, and run the service with the lowest practical privileges.
- Review configuration, roles, tokens, network paths, and exposed endpoints connected to EGroupware; remove access that is not required.
- Review process, shell, web, audit, and network logs for unexpected commands, child processes, downloads, callbacks, or changed files.
- If exploitation is suspected, isolate affected assets, preserve evidence, rotate exposed credentials or keys, restore trusted data, and rebuild compromised systems before returning them to service.
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Verify the fix
- Confirm every affected asset now runs the fixed vendor-supported release or has the documented mitigation for CVE-2026-40187 in place.
- Use a safe regression test to confirm the affected code or command execution path no longer produces the vulnerable behavior.
- Confirm temporary access controls, endpoint restrictions, network blocks, and least-privilege settings remain effective after the update.
- Review post-remediation logs and rerun Fixnx plus the relevant package, dependency, firmware, browser, or product-specific security check.
- Document affected assets, versions, changes, validation evidence, reviewed logs, and any credential rotation, cleanup, or replacement completed.
Related categories
Related security risks
More published guidance from the same primary category.
Trusted references
FAQ
What is affected by CVE-2026-40187?
EGroupware versions listed as affected should be reviewed: <= 26.0.
What should I fix first?
Start with internet-facing sites, admin panels, login flows, plugins, themes, modules, packages, and systems that process user-controlled input or sensitive data.
How do I confirm the fix worked?
Apply the patched version or mitigation, clear caches where relevant, retest the affected workflow, and run a new Fixnx scan to verify public website exposure signals.
How are Fixnx security risk categories chosen?
Fixnx keeps one canonical risk page and assigns only broad, relevant categories such as ecosystem, technology area, or vulnerability class.