Insecure Deserialization
Insecure deserialization occurs when an application converts serialized data (a stream of bytes representing an object's state) back into a living object without proper validation.
How It Works
Insecure deserialization occurs when an application converts serialized data (a stream of bytes representing an object's state) back into a living object without proper validation. Serialization frameworks in languages like Java, PHP, Python, and .NET allow objects to be transformed into byte streams for storage or transmission, then reconstructed later. The vulnerability arises because deserialization can trigger code execution through the object's methods during reconstruction.
Attackers exploit this by crafting malicious serialized payloads containing specially chosen objects that chain together through "gadget chains" — sequences of method calls in existing application libraries. When the application deserializes the attacker's payload, it automatically invokes these methods in sequence, ultimately achieving arbitrary code execution. For example, in Java applications, an attacker might create a serialized object that, when deserialized, triggers a chain through Apache Commons Collections classes, ending in runtime command execution.
The attack typically begins with identifying an endpoint that accepts serialized data — often in cookies, API parameters, or message queue payloads. The attacker then uses tools like ysoserial (Java) or phpggc (PHP) to generate weaponized payloads targeting known gadget chains in the application's dependencies. Because deserialization happens automatically and often before any application logic executes, these attacks frequently bypass authentication and input validation.
Impact
- Remote code execution — attackers gain complete control of the server, executing arbitrary system commands
- Authentication bypass — deserializing manipulated user/session objects grants unauthorized access without credentials
- Privilege escalation — modifying serialized role or permission objects to gain administrative access
- Data exfiltration — reading sensitive files or database contents through executed code
- Denial of service — crafting objects that consume excessive memory or CPU during deserialization
Real-World Examples
SolarWinds Web Help Desk suffered two separate deserialization vulnerabilities in rapid succession. CVE-2025-40551 allowed unauthenticated attackers to achieve remote code execution by sending malicious serialized Java objects to the application. Even after patching, researchers discovered a second deserialization flaw in the same product, demonstrating how deeply embedded these vulnerabilities can be in application architectures.
Jenkins automation servers have experienced multiple Java deserialization vulnerabilities where attackers exploited the CLI protocol to send crafted objects, gaining full control over build servers. These attacks were particularly severe because Jenkins instances often have extensive network access and stored credentials for deploying applications.
WordPress and other PHP applications have faced attacks through unserialize() vulnerabilities in plugins, where attackers embedded malicious PHP objects in user-controllable data fields. Successful exploitation enabled attackers to install backdoors by writing arbitrary PHP files to the web root.
Mitigation
- Avoid deserializing untrusted data entirely — redesign systems to use data-only formats like JSON instead of native serialization
- Implement strict allowlists — configure deserialization libraries to only accept explicitly permitted classes, blocking all others
- Apply cryptographic signatures — sign serialized data and validate signatures before deserialization to ensure integrity
- Use isolated environments — deserialize in sandboxed processes with minimal privileges to contain potential exploitation
- Update vulnerable libraries — patch frameworks and remove dependencies with known gadget chains
- Monitor deserialization activity — log and alert on deserialization operations, especially from external sources
Recent CVEs (848)
In checkKeyIntentParceledCorrectly of AccountManagerService.java, there is a possible way to bypass parcel mismatch mitigation due to unsafe deserialization. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. No vendor patch available.
Deserialization of Untrusted Data vulnerability in NotFound ARPrice allows Object Injection.0.3. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Deserialization of Untrusted Data vulnerability in NotFound ARPrice allows Object Injection.0.3. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
The String locator plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 2.6.6 via deserialization of untrusted input in the 'recursive_unserialize_replace'. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Epss exploitation probability 16.5%.
The a+HRD from aEnrich Technology has an Insecure Deserialization vulnerability, allowing remote attackers with database modification privileges and regular system privileges to perform arbitrary. Rated high severity (CVSS 7.2), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
and potential remote code execution on workstation when a non-admin authenticated user opens a malicious project file. Rated high severity (CVSS 8.5), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
Matrix Media Repo (MMR) is a highly configurable multi-homeserver media repository for Matrix. Rated medium severity (CVSS 6.8), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
MSFM before 2025.01.01 was discovered to contain a fastjson deserialization vulnerability via the component system/table/editField. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
MSFM before 2025.01.01 was discovered to contain a fastjson deserialization vulnerability via the component system/table/add. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
MSFM before 2025.01.01 was discovered to contain a fastjson deserialization vulnerability via the component system/table/addField. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
MSFM before v2025.01.01 was discovered to contain a deserialization vulnerability via the pom.xml configuration file. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
Microsoft Excel Security Feature Bypass Vulnerability. Rated high severity (CVSS 7.8), this vulnerability is no authentication required, low attack complexity. This Deserialization of Untrusted Data vulnerability could allow attackers to execute arbitrary code through malicious serialized objects.
A vulnerability was found in AquilaCMS 1.412.13. Rated medium severity (CVSS 6.9), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Deserialization of untrusted data in Ivanti EPM before the 2024 January-2025 Security Update and 2022 SU6 January-2025 Security Update allows a remote unauthenticated attacker to achieve remote code. Rated high severity (CVSS 7.8), this vulnerability is no authentication required, low attack complexity. Epss exploitation probability 26.5% and no vendor patch available.
Deserialization of Untrusted Data vulnerability in GiveWP GiveWP allows Object Injection.19.3. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
The GiveWP - Donation Plugin and Fundraising Platform plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 3.19.2 via deserialization of untrusted input. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Epss exploitation probability 27.5%.
The Coupon X: Discount Pop Up, Promo Code Pop Ups, Announcement Pop Up, WooCommerce Popups plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 1.3.5 via. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable. No vendor patch available.
Deserialization of Untrusted Data vulnerability in Drupal Eloqua allows Object Injection.X-* before 7.X-1.15. Rated medium severity (CVSS 6.6), this vulnerability is remotely exploitable. No vendor patch available.
Deserialization of Untrusted Data vulnerability in Drupal Mailjet allows Object Injection.0.0 before 4.0.1. Rated medium severity (CVSS 6.6), this vulnerability is remotely exploitable. No vendor patch available.
Deserialization of Untrusted Data vulnerability in Drupal Node export allows Object Injection.X-* before 7.X-3.3. Rated medium severity (CVSS 6.6), this vulnerability is remotely exploitable. No vendor patch available.
Deserialization of Untrusted Data vulnerability in Drupal Monster Menus allows Object Injection.0.0 before 9.3.4, from 9.4.0 before 9.4.2. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Deserialization of Untrusted Data vulnerability in Konrad Karpieszuk WC Price History for Omnibus allows Object Injection.1.4. Rated high severity (CVSS 7.2), this vulnerability is remotely exploitable, low attack complexity. Epss exploitation probability 14.8% and no vendor patch available.
Vendor: The Apache Software Foundation Versions Affected: Apache OpenMeetings from 2.1.0 before 8.0.0 Description: Default clustering instructions at https://openmeetings.apache.org/Clustering.html. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Invoice Ninja before 5.10.43 allows remote code execution from a pre-authenticated route when an attacker knows the APP_KEY. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. Epss exploitation probability 39.4% and no vendor patch available.
Crater Invoice application allows unauthenticated remote command execution through Laravel session cookie deserialization when the APP_KEY is known. Attackers who obtain the application key can forge session cookies containing serialized PHP objects that execute arbitrary commands on the server.
Deserialization of Untrusted Data vulnerability in plainware.com PlainInventory allows Object Injection.1.6. Rated high severity (CVSS 8.1), this vulnerability is remotely exploitable, no authentication required. No vendor patch available.
Deserialization of Untrusted Data vulnerability in plainware.com Locatoraid Store Locator allows Object Injection.9.50. Rated high severity (CVSS 8.1), this vulnerability is remotely exploitable, no authentication required. No vendor patch available.
Deserialization of Untrusted Data vulnerability in Amento Tech Pvt ltd WPGuppy allows Object Injection.1.0. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
The Compare Products for WooCommerce plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 3.2.1 via deserialization of untrusted input from the. Rated high severity (CVSS 8.1), this vulnerability is remotely exploitable, no authentication required. No vendor patch available.
The Custom Product Tabs for WooCommerce plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 1.8.5 via deserialization of untrusted input in the. Rated high severity (CVSS 7.2), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
In Modem, there is a possible system crash due to a logic error. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
A vulnerability was found in wangl1989 mysiteforme 1.0 and classified as critical. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
The UpdraftPlus: WP Backup & Migration Plugin plugin for WordPress is vulnerable to PHP Object Injection in all versions from 1.23.8 to 1.24.11 via deserialization of untrusted input in the. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
The Backup Migration plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 1.4.6 via deserialization of untrusted input in the. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Microsoft SharePoint Server Remote Code Execution Vulnerability. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. This Deserialization of Untrusted Data vulnerability could allow attackers to execute arbitrary code through malicious serialized objects.
A vulnerability, which was classified as critical, has been found in fhs-opensource iparking 1.5.22.RELEASE. Rated medium severity (CVSS 6.3), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
Remote unauthenticated attackers can execute arbitrary code on Adobe ColdFusion servers through Java deserialization flaws in the bundled Apache BlazeDS library. This critical vulnerability affects ColdFusion 10 (all updates through 22), ColdFusion 11 (through Update 11), and ColdFusion 2016 (through Update 3). CISA confirms active exploitation in the wild with publicly available exploit code (Exploit-DB 43993), and EPSS scoring at 93.36% (100th percentile) indicates extremely high real-world exploitation likelihood. The network-accessible attack vector requiring no authentication or user interaction makes this a top-priority remediation target for any organization running affected ColdFusion versions.
Remote code execution in IBM Sterling B2B Integrator, Sterling Integrator, and Tivoli Common Reporting allows unauthenticated network attackers to execute arbitrary commands by sending malicious serialized Java objects exploiting the Apache Commons Collections InvokerTransformer class. This vulnerability is confirmed actively exploited in the wild per CISA KEV, with public exploit code available (Exploit-DB 41613) and an exceptionally high EPSS score of 93.49%, indicating near-certain exploitation probability. Affected products include Sterling B2B Integrator 5.2, Sterling Integrator 5.1, and Tivoli Common Reporting versions 2.1 through 3.1.2.1.
Quick Facts
- Typical Severity
- CRITICAL
- Category
- web
- Total CVEs
- 848