CVE-2026-111234 in SimplePie
Summary
by MITRE • 10/15/2026
SimplePie through 1.9.0 contains a local file read vulnerability that allows malicious feed servers to read server files by supplying file:// URLs in redirects or autodiscovery links. Attackers can return a Location header or feed link pointing to a file:// path, causing file_get_contents() to read files accessible to the web server process.
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Analysis
by VulDB Data Team • 10/15/2026
The vulnerability identified within SimplePie versions up to 1.9.0 represents a critical local file inclusion flaw rooted in improper validation of external inputs during the parsing and redirection processes of RSS feed data. As an open-source PHP library widely used for aggregating XML-based web feeds, SimplePie is designed to fetch content from remote sources, parse it, and present it to applications. The core technical failure lies in how the library handles HTTP redirects and autodiscovery mechanisms when processing these feeds. Specifically, the software fails to adequately sanitize or restrict URL schemes before passing them to underlying PHP functions such as file_get_contents(). This oversight allows an attacker who controls a malicious feed server to inject specially crafted URLs that utilize the file:// protocol scheme instead of standard http or https protocols.
When a victim application utilizes SimplePie to fetch content from this compromised source, the library processes the redirect instructions or autodiscovery links provided by the attacker. Instead of rejecting non-HTTP schemes as potentially unsafe, the vulnerable version passes these file-based paths directly into PHP's stream handling functions. Consequently, if the web server process has read permissions for specific files on the local filesystem, those contents are retrieved and returned to the application context. This mechanism effectively bypasses network-level restrictions because the data is sourced locally from the disk rather than over a remote connection, making it difficult to detect via standard intrusion detection systems that monitor outbound traffic or external requests.
The operational impact of this vulnerability is severe, primarily manifesting as Local File Read (LFR) and potentially leading to Remote Code Execution depending on the surrounding application logic. An attacker can exploit this flaw to read sensitive configuration files such as /etc/passwd, database credentials stored in config.php, SSH keys, or other proprietary data residing within directories accessible by the web server user account. This information disclosure provides a significant foothold for further exploitation, allowing adversaries to map out the system architecture, steal authentication tokens, and identify additional attack vectors. The severity is exacerbated by the fact that feed aggregation often runs with elevated privileges relative to static assets, increasing the scope of readable files.
From a classification perspective, this vulnerability aligns closely with CWE-20 Improper Input Validation, as the root cause is the failure to restrict input based on expected types or schemes. It also maps directly to CWE-94 Improper Control of Generation of Code (Code Injection) in its broader context of untrusted data influencing system behavior, and specifically relates to CWE-78 OS Command Injection if the read content leads to command execution through subsequent processing steps. In terms of offensive security frameworks, this exploit technique corresponds to ATT&CK tactic T1083 File and Directory Discovery, where adversaries seek to enumerate sensitive files on a compromised host to facilitate lateral movement or privilege escalation.
Mitigation strategies must focus on immediate patching and defensive coding practices. The primary remediation is upgrading SimplePie to version 1.9.1 or later, where the developers have implemented stricter validation for URL schemes during redirect handling and autodiscovery phases. For applications unable to upgrade immediately due to compatibility constraints, a temporary workaround involves implementing custom input sanitization layers that explicitly whitelist allowed URI schemes such as http and https while blocking file://, ftp://, and other potentially dangerous protocols before they reach the SimplePie parsing engine. Additionally, administrators should ensure that the web server process operates under a restricted user account with minimal filesystem permissions to limit the blast radius of any successful exploitation attempt. Regular security audits focusing on third-party library dependencies are essential to maintain resilience against such input validation flaws in modern software supply chains.