CVE-2026-27706: Plane Project Management Tool SSRF Flaw

CVE-2026-27706 Overview

CVE-2026-27706 is a Full Read Server-Side Request Forgery (SSRF) vulnerability discovered in Plane, an open-source project management tool. The vulnerability exists in the "Add Link" feature and allows an authenticated attacker with general user privileges to send arbitrary GET requests to the internal network and exfiltrate the full response body. By exploiting this vulnerability, an attacker can steal sensitive data from internal services and cloud metadata endpoints.

Critical Impact

Authenticated attackers can access internal network resources and cloud metadata endpoints, potentially exposing sensitive infrastructure secrets, API keys, and configuration data.

Affected Products

• Plane versions prior to 1.2.2

Discovery Timeline

• 2026-02-25 - CVE CVE-2026-27706 published to NVD
• 2026-02-25 - Last updated in NVD database

Technical Details for CVE-2026-27706

Vulnerability Analysis

This vulnerability is classified as CWE-918 (Server-Side Request Forgery). The SSRF flaw in Plane's "Add Link" feature allows authenticated users to manipulate the application into making HTTP GET requests to arbitrary destinations. Unlike blind SSRF vulnerabilities where attackers cannot see the response, this is a Full Read SSRF, meaning the complete response body from internal requests is returned to the attacker.

The network-accessible attack vector with low complexity makes this vulnerability particularly concerning for organizations running Plane in environments with access to sensitive internal services or cloud infrastructure.

Root Cause

The root cause of this vulnerability lies in insufficient validation and sanitization of user-supplied URLs in the "Add Link" feature. When a user adds a link, the application server fetches the URL to retrieve metadata or preview information. Without proper restrictions on the destination of these requests, attackers can direct the server to make requests to internal IP addresses, localhost services, or cloud metadata endpoints (such as 169.254.169.254 on AWS).

Attack Vector

An authenticated attacker exploits this vulnerability through the following attack flow:

1. The attacker authenticates to the Plane application with standard user credentials
2. The attacker navigates to a feature that allows adding links (such as adding a link to a project or issue)
3. Instead of providing a legitimate external URL, the attacker supplies an internal URL (e.g., http://169.254.169.254/latest/meta-data/iam/security-credentials/)
4. The Plane server makes a GET request to the specified internal URL
5. The full response from the internal service is returned to the attacker, exposing sensitive information

This attack can be used to access cloud metadata services, internal APIs, administrative interfaces, and other services not exposed to the public internet.

Detection Methods for CVE-2026-27706

Indicators of Compromise

• Unusual outbound requests from the Plane application server to internal IP ranges (e.g., 10.x.x.x, 172.16.x.x, 192.168.x.x)
• Requests to cloud metadata endpoints such as 169.254.169.254
• Access logs showing requests to localhost (127.0.0.1) services from the Plane server
• Anomalous link additions containing internal IP addresses or non-standard URLs

Detection Strategies

• Monitor application logs for URL submissions containing private IP address ranges or metadata endpoints
• Implement network-level monitoring to detect unusual traffic patterns from the Plane application server to internal services
• Review web application firewall (WAF) logs for SSRF patterns in user-submitted URLs
• Enable detailed logging on the Plane application to track link additions and associated metadata fetch operations

Monitoring Recommendations

• Configure alerts for any requests from the Plane server to cloud metadata services
• Implement egress filtering monitoring to detect requests to non-whitelisted internal services
• Deploy application performance monitoring (APM) to identify unusual server-side request patterns
• Regularly audit link additions in Plane for suspicious internal URLs

How to Mitigate CVE-2026-27706

Immediate Actions Required

• Upgrade Plane to version 1.2.2 or later immediately
• Review application logs for evidence of exploitation attempts
• Audit any sensitive data accessible from the Plane server's network position
• If immediate upgrade is not possible, restrict network egress from the Plane application server

Patch Information

The vulnerability has been fixed in Plane version 1.2.2. Organizations should upgrade to this version or later to remediate the vulnerability. For detailed patch information, refer to the GitHub Release v1.2.2 and the GitHub Security Advisory GHSA-jcc6-f9v6-f7jw.

Workarounds

• Implement network-level egress filtering to prevent the Plane server from accessing internal resources and cloud metadata endpoints
• Deploy a web application firewall (WAF) with SSRF protection rules to block requests containing internal IP addresses
• Restrict network access for the Plane application server using security groups or firewall rules to limit outbound connectivity
• Consider placing the Plane application in an isolated network segment with no access to sensitive internal services

# Example: Block access to cloud metadata endpoint using iptables
iptables -A OUTPUT -d 169.254.169.254 -j DROP

# Example: Block access to private IP ranges from the Plane server
iptables -A OUTPUT -d 10.0.0.0/8 -j DROP
iptables -A OUTPUT -d 172.16.0.0/12 -j DROP
iptables -A OUTPUT -d 192.168.0.0/16 -j DROP