CVE-2026-55526 in PraisonAI
Summary
by MITRE • 08/25/2026
PraisonAI is a multi-agent teams system. Prior to praisonaiagents 1.6.58, spider_tools._host_is_blocked() does not resolve ordinary hostnames before scrape_page fetches them. A hostname such as 127.0.0.1.nip.io passes validation and resolves to loopback, permitting internal HTTP access. The fix uses socket.getaddrinfo and fails closed on DNS errors. This issue is fixed in version 1.6.58.
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Analysis
by VulDB Data Team • 08/25/2026
The vulnerability identified in PraisonAI versions prior to 1.6.58 represents a critical flaw in the hostname validation logic within the spider_tools module, specifically affecting the _host_is_blocked function. As a multi-agent team system designed for automated web interactions and data scraping, PraisonAI relies on robust security controls to prevent agents from accessing unintended or sensitive internal resources. The core technical deficiency lies in the order of operations during URL processing. Prior to the fix, the validation mechanism failed to perform standard DNS resolution before evaluating whether a hostname was blocked. This oversight allowed specially crafted hostnames that encode IP addresses within their domain structure, such as 127.0.0.1.nip.io, to bypass security checks. The nip.io service is designed to resolve any subdomain into the corresponding IPv4 address specified in the label hierarchy, meaning this specific hostname resolves directly to the loopback interface address 127.0.0.1. Because the validation logic did not resolve these hostnames beforehand, it treated them as arbitrary external domains rather than internal addresses, permitting the scrape_page function to proceed with fetching content from local services that should have been restricted.
This flaw creates a significant risk of Server-Side Request Forgery (SSRF) and unauthorized access to internal network resources. By allowing agents to resolve hostnames into loopback addresses through DNS encoding techniques, an attacker or a misconfigured agent could potentially interact with localhost-based applications, such as database management interfaces, administrative panels, or other microservices running on the same host but not exposed externally. This bypasses perimeter security controls that typically rely on IP whitelisting or domain blocking lists, as the initial validation step was effectively neutralized by the DNS resolution behavior of services like nip.io. The operational impact includes potential data exfiltration from internal systems, unauthorized configuration changes to local services, and broader compromise of the host environment if those internal services lack proper authentication or network segmentation. This aligns with CWE-918, which addresses Server-Side Request Forgery (SSRF) flaws where a server makes requests based on user-supplied input without sufficient validation, as well as ATT&CK technique T1557, specifically Adversary-in-the-Middle scenarios that can be facilitated by SSRF to intercept or manipulate internal communications.
The remediation implemented in version 1.6.58 addresses this vulnerability by enforcing strict DNS resolution prior to any access control decisions. The updated code utilizes socket.getaddrinfo to explicitly resolve the hostname into its corresponding IP address before evaluating it against blocked lists. This ensures that encoded IP addresses are decoded and recognized as internal loopback or private network ranges, triggering a fail-closed response if they match restricted criteria. By resolving DNS records first, the system prevents attackers from using domain-based obfuscation techniques to bypass security filters. Organizations utilizing PraisonAI must upgrade immediately to version 1.6.58 or later to mitigate this risk. Additionally, it is recommended to implement defense-in-depth strategies by configuring network-level firewalls to restrict outbound connections from agent processes and validating all URLs against a strict allowlist of permitted domains rather than relying solely on blocklists. Regular security audits should also include testing for SSRF vulnerabilities using DNS rebinding techniques to ensure that future updates maintain robust input validation practices.