CVE-2026-12813 Overview
CVE-2026-12813 is a Server-Side Request Forgery (SSRF) vulnerability in Activepieces versions up to 0.83.0. The flaw resides in the handleUrlFile function within packages/server/engine/src/lib/variables/processors/file.ts, part of the File URL Handler component. An authenticated remote attacker can manipulate URL inputs to coerce the server into issuing arbitrary outbound requests. The vendor was contacted prior to disclosure but did not respond, and a public exploit is available. The vulnerability is tracked under CWE-918: Server-Side Request Forgery.
Critical Impact
Remote attackers with low privileges can abuse the File URL Handler to reach internal services, cloud metadata endpoints, and other restricted network resources reachable from the Activepieces server.
Affected Products
- Activepieces versions up to and including 0.83.0
- Component: File URL Handler (packages/server/engine/src/lib/variables/processors/file.ts)
- Function: handleUrlFile
Discovery Timeline
- 2026-06-21 - CVE-2026-12813 published to NVD
- 2026-06-22 - Last updated in NVD database
Technical Details for CVE-2026-12813
Vulnerability Analysis
The vulnerability exists in the handleUrlFile function inside packages/server/engine/src/lib/variables/processors/file.ts. This function processes user-supplied URLs to retrieve file content for use within Activepieces flows. The handler does not adequately validate or restrict destination addresses before issuing the outbound HTTP request.
Because the request originates from the Activepieces server, attackers can target hosts that are otherwise unreachable from the public internet. Typical SSRF targets include cloud instance metadata endpoints, internal admin panels, and services bound to loopback interfaces. The attack requires only network access and low-privilege authentication, with no user interaction required.
A public proof of concept describing the exploitation path is documented in the GitHub SSRF Vulnerability Report.
Root Cause
The root cause is insufficient validation of the URL parameter passed to handleUrlFile. The function does not enforce an allowlist of permitted destinations, does not filter private and link-local IP ranges, and does not block redirects to internal addresses. Any string parseable as a URL is dispatched as an outbound request.
Attack Vector
An authenticated attacker submits a crafted file URL through an Activepieces flow or piece configuration that invokes handleUrlFile. The server retrieves the URL using its own network identity. Targets include http://127.0.0.1 services, http://169.254.169.254 cloud metadata endpoints, and internal corporate hostnames. Response content may be returned to the attacker, depending on how the flow processes the fetched file. Additional technical context is published in the VulDB CVE-2026-12813 listing.
No verified exploit code is reproduced here. Refer to the public advisory for proof-of-concept details.
Detection Methods for CVE-2026-12813
Indicators of Compromise
- Outbound HTTP requests from the Activepieces server to private IP ranges (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16) or loopback 127.0.0.0/8.
- Requests from the Activepieces process to cloud metadata endpoints such as 169.254.169.254 or metadata.google.internal.
- Unexpected URL values in flow configurations referencing internal hostnames or non-standard ports.
Detection Strategies
- Inspect application logs from the engine package for invocations of handleUrlFile with non-public destination URLs.
- Correlate authenticated user sessions with outbound network connections made by the Activepieces server process.
- Alert on DNS resolutions from the Activepieces host that return RFC1918 or link-local addresses.
Monitoring Recommendations
- Deploy egress filtering at the network layer and log every blocked attempt from the Activepieces server.
- Forward web proxy and DNS logs to a centralized analytics platform to baseline normal outbound destinations.
- Review flow creation and edit events for URL parameters introduced by low-privilege accounts.
How to Mitigate CVE-2026-12813
Immediate Actions Required
- Restrict outbound network access from the Activepieces server using firewall rules that deny private, loopback, and metadata IP ranges.
- Limit which authenticated users can author or modify flows that consume file URLs.
- Audit existing flows for handleUrlFile usage referencing untrusted or internal URLs and remove suspicious entries.
Patch Information
No vendor patch was identified at the time of publication. The vendor did not respond to disclosure outreach. Monitor the Activepieces repository for fixed releases beyond 0.83.0 and review the VulDB vulnerability record for updates.
Workarounds
- Place the Activepieces server behind an egress proxy that enforces destination allowlists for outbound HTTP requests.
- Block access from the Activepieces host to cloud metadata services using IMDSv2 enforcement or network ACLs.
- Disable or restrict pieces and flow features that rely on user-supplied URLs until a patched version is available.
# Example iptables egress restrictions for the Activepieces host
iptables -A OUTPUT -d 127.0.0.0/8 -j REJECT
iptables -A OUTPUT -d 10.0.0.0/8 -j REJECT
iptables -A OUTPUT -d 172.16.0.0/12 -j REJECT
iptables -A OUTPUT -d 192.168.0.0/16 -j REJECT
iptables -A OUTPUT -d 169.254.169.254/32 -j REJECT
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
