CVE-2026-78535 in Photolia Plugin
Summary
by MITRE • 10/10/2026
Unauthenticated PHP Object Injection in Photolia <= 1.0.3 versions.
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Analysis
by VulDB Data Team • 10/11/2026
The vulnerability identified as an unauthenticated PHP object injection flaw within Photolia versions up to and including 1.0.3 represents a critical security deficiency that allows attackers to execute arbitrary code or manipulate application state without valid credentials. This type of vulnerability stems from the improper handling of user-supplied input during the deserialization process, where data is converted back into objects in memory. In PHP applications, object injection often occurs when functions such as unserialize() are invoked with parameters derived directly from HTTP requests, cookies, or other external sources that have not been adequately sanitized or validated against a whitelist of expected classes and properties. The absence of authentication requirements for this specific vector significantly elevates the risk profile, enabling any remote actor on the network to exploit the flaw without needing prior access privileges.
From a technical perspective, PHP object injection exploits the internal mechanisms used by the language to reconstruct objects from serialized strings. When an application accepts user input and passes it directly into deserialization functions, an attacker can craft a malicious payload containing a specially constructed serialized string. This payload typically includes references to classes that possess magic methods such as __wakeup(), __destruct(), or __toString(). By manipulating these properties, the attacker can trigger unintended side effects within the application's execution flow. In many cases, this leads to remote code execution if the injected object interacts with system-level functions like eval() or file_get_contents(). The vulnerability is fundamentally rooted in CWE-502, which describes deserialization of untrusted data, a category known for its potential to bypass security controls and compromise application integrity.
The operational impact of this vulnerability is severe, as it can lead to complete compromise of the underlying server hosting the Photolia instance. An attacker leveraging this flaw could potentially read sensitive configuration files containing database credentials or API keys, modify user-generated content stored in the system's file structure, or establish a persistent backdoor for future access. Furthermore, because the vulnerability is unauthenticated, it can be exploited via automated scanning tools across the internet, leading to widespread compromise of vulnerable instances shortly after public disclosure. This aligns with MITRE ATT&CK technique T1059, specifically command and script interpretation, as well as T1203 for exploitation of client software or web applications where no user interaction is required beyond sending a crafted request.
Mitigation strategies must focus on eliminating the root cause by avoiding direct deserialization of untrusted data entirely. If object serialization is necessary within the application logic, developers should implement strict class whitelisting to ensure that only expected and safe classes are instantiated during the deserialization process. Additionally, employing integrity checks such as HMAC signatures for serialized payloads can prevent tampering with the data structure before it reaches the unserialize function. For organizations currently running Photolia versions 1.0.3 or earlier, immediate upgrading to a patched version is the most effective remediation step provided by the vendor. In cases where an update is not immediately available, implementing web application firewall rules that detect and block common PHP object injection payloads in HTTP parameters can provide a temporary layer of defense while longer-term architectural fixes are developed.