CVE-2026-86735 in Snipe-IT
Summary
by MITRE • 09/08/2026
snipe-it versions before 8.7.0 contain a server-side request forgery vulnerability in the ExternalUrl validation rule that fails to detect IPv6 transition addresses encoding private IPv4 targets. Attackers with super-admin privileges can configure webhook URLs using NAT64, 6to4, or Teredo transition addresses to bypass SSRF guards and access internal services or cloud metadata endpoints.
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Analysis
by VulDB Data Team • 09/08/2026
The vulnerability identified in Snipe-IT versions prior to 8.7.0 represents a critical server-side request forgery (SSRF) flaw rooted in the application's input validation logic for external URLs. Specifically, the ExternalUrl validation rule fails to adequately sanitize or validate IPv6 transition addresses that encode private IPv4 destinations. This oversight allows attackers who possess super-admin privileges to manipulate webhook configurations by specifying target URLs using NAT64, 6to4, or Teredo address formats. These specific encoding methods effectively mask internal IP ranges within valid-looking public IPv6 structures, thereby bypassing the application's SSRF protection mechanisms which typically rely on simple private IP range checks that do not account for these complex translation schemes.
From a technical perspective, this flaw exploits the ambiguity in how network stacks and validation libraries interpret transition addresses. NAT64, 6to4, and Teredo are designed to facilitate communication between IPv6-only networks and IPv4 infrastructure by embedding IPv4 addresses within IPv6 packets. The vulnerability arises because the validation logic likely checks for private IPv4 ranges such as 10.x.x.x, 172.16-31.x.x, or 192.168.x.x in their standard dotted-decimal format but fails to decode and inspect these addresses when they are encapsulated within transition address formats. Consequently, the application perceives the request as targeting a public internet resource rather than an internal service, allowing the server-side component to initiate HTTP requests to restricted internal endpoints or cloud metadata services that should be inaccessible from external contexts.
The operational impact of this vulnerability is severe for organizations running affected versions with super-admin accounts compromised or accessible by malicious insiders. An attacker can leverage this SSRF capability to probe and access internal network services, such as database servers, administrative panels, or microservices hosted on the same infrastructure but not exposed to the public internet. Furthermore, in cloud environments, this vulnerability enables unauthorized access to instance metadata endpoints, which often contain sensitive credentials, API keys, and configuration details necessary for further lateral movement within the environment. This effectively undermines network segmentation strategies that rely on application-level filtering to protect internal assets from web-facing applications.
This issue aligns with CWE-918, Server-Side Request Forgery (SSRF), specifically highlighting a failure in input validation regarding IP address parsing and normalization. It also maps to MITRE ATT&CK technique T1504.003, Web Service Discovery, as the attacker uses the forged requests to enumerate internal services, and potentially T1078.002 for accessing cloud metadata if deployed on public infrastructure. The vulnerability underscores the complexity of modern network protocols and the necessity for robust validation logic that accounts for protocol translation layers rather than relying solely on static IP range checks.
To mitigate this risk, organizations must immediately upgrade Snipe-IT to version 8.7.0 or later, where the ExternalUrl validation rule has been patched to correctly decode and inspect transition addresses for private IPv4 ranges. In addition to upgrading, administrators should enforce strict least-privilege principles by limiting super-admin access to trusted personnel only. Network-level controls such as egress filtering can also provide a secondary layer of defense by blocking outbound connections from the Snipe-IT server to known internal IP ranges or cloud metadata endpoints that are not required for normal application operation. Regular security audits and penetration testing should include specific checks for SSRF vulnerabilities involving IPv6 transition addresses to ensure comprehensive protection against this class of attacks.