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CVE-2021-21707 is a filename handling flaw in PHP affecting 7.3.x before 7.3.33, 7.4.x before 7.4.26, and 8.0.x before 8.0.13. Certain XML parsing functions, including simplexml_load_file(), URL-decode the supplied filename before opening it. If the attacker-controlled filename contains a URL-encoded NUL byte, the decoded NUL may be interpreted as the end of the string, causing filename truncation. As a result, the function may access a different file than the caller intended. The issue is effectively an improper neutralization of a null byte in a file path during XML file loading, creating a path interpretation discrepancy between application logic and the underlying file access behavior.
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1 valid exploit after Mallory filtered fakes, detection scripts, and README-only repos.
This repository contains a single Java file, 'PhpReverseShell81.java', and a minimal README. The Java program is an exploit targeting PHP 8.1 (or similarly vulnerable PHP environments) that are misconfigured to execute code from HTTP headers. The exploit works by sending an HTTP GET request to a user-supplied target URL, setting a custom header ('User-Agentt') with a payload that attempts to execute a bash reverse shell command on the target. The payload instructs the target to connect back to the attacker's machine (specified by host IP and port) and provide a shell. The attacker must be listening on the specified port to receive the connection. The exploit assumes the target is vulnerable to code execution via HTTP headers, a scenario seen in some PHP 8.1 dev builds or misconfigurations. The repository is straightforward, with the main exploit logic contained in the Java file and no additional scripts or modules.
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1 sources tracked across advisories and community write-ups. News coverage will land here when it surfaces.
No news coverage yet. Advisories and community discussion only.
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Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.