# CVE-2026-115720: Frappe Builder server-side request forgery via redirect bypass

Source: https://junglewise.ai/threats/cve-2026-115720-frappe-builder-before-1-36-1-contains-a-server-side-request  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-26. Updated: 2026-10-26  
License: CC BY 4.0 with a link back

CVE-2026-115720 · Severity: medium · CVSS 5 · Published 2026-10-26

Frappe Builder is a visual page builder that allows authenticated users to process remote URLs. A vulnerability in the URL validation logic permits attackers to supply a public URL that redirects to internal systems such as cloud metadata services, enabling unauthorized access to sensitive configuration data or triggering network outages through hung requests.

Technologies: [Frappe Builder](https://junglewise.ai/threats/technologies/frappe-builder). Vendors: [Frappe](https://junglewise.ai/threats/vendors/frappe).

## Quick answers

**Is CVE-2026-115720 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-115720 being exploited in the wild.

**How severe is CVE-2026-115720?** Medium severity, with a CVSS score of 5, published 26 October 2026.

**Which products and versions are affected?** Frappe Builder before 1.36.1.

**Is there a fix for CVE-2026-115720?** Yes: fixed in 1.36.1. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-115720 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-115720?** Check whether you run Frappe Builder at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 1.36.1

## Technical details

The builder/api.py module validates only the initial hostname against a private-IP blocklist before following HTTP redirects, creating a TOCTOU race condition. Attackers can supply a public URL that redirects to internal or link-local addresses (including 100.100.100.200 metadata services), bypass DNS rebinding via second-order host resolution, or trigger denial of service through missing timeouts on the requests.get() call. The convert_to_webp endpoint lacks a permission decorator, exposing it to any authenticated user.

## Affected products

- Frappe Builder before 1.36.1

## Timeline

- 2026-10-26: disclosed
- 2026-10-23: patched: Version 1.36.1 released

## References

- [https://github.com/frappe/builder/releases/tag/v1.36.1](https://github.com/frappe/builder/releases/tag/v1.36.1)
- [https://github.com/frappe/builder/security/advisories/GHSA-hvrf-fhv3-3v7p](https://github.com/frappe/builder/security/advisories/GHSA-hvrf-fhv3-3v7p)

## Related threats

- [Frappe Builder missing authorization in improve_prompt endpoint](https://junglewise.ai/threats/cve-2026-115718-frappe-builder-versions-1-33-0-before1-36-0-contain-a-missing)
- [Frappe Builder SSRF in convert_to_webp API](https://junglewise.ai/threats/cve-2026-115717-frappe-builder-versions-before-1-36-1-contain-a-server-side)