Weakness (CWE)
CWE-20: Improper Input Validation
The product receives input or data, but it does
not validate or incorrectly validates that the input has the
properties that are required to process the data safely and
correctly.
How to prevent it (8 mitigations)
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Architecture and Design
Consider using language-theoretic security (LangSec) techniques that characterize inputs using a formal language and build "recognizers" for that language. This effectively requires parsing to be a distinct layer that effectively enforces a boundary between raw input and internal data representations, instead of allowing parser code to be scattered throughout the program, where it could be subject to errors or inconsistencies that create weaknesses. [REF-1109] [REF-1110] [REF-1111]
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Architecture and Design
Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
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Architecture and Design, Implementation
Understand all the potential areas where untrusted inputs can enter the product, including but not limited to: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls.
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Implementation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue."
Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
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Architecture and Design
For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
Even though client-side checks provide minimal benefits with respect to server-side security, they are still useful. First, they can support intrusion detection. If the server receives input that should have been rejected by the client, then it may be an indication of an attack. Second, client-side error-checking can provide helpful feedback to the user about the expectations for valid input. Third, there may be a reduction in server-side processing time for accidental input errors, although this is typically a small savings.
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Implementation
When your application combines data from multiple sources, perform the validation after the sources have been combined. The individual data elements may pass the validation step but violate the intended restrictions after they have been combined.
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Implementation
Be especially careful to validate all input when invoking code that crosses language boundaries, such as from an interpreted language to native code. This could create an unexpected interaction between the language boundaries. Ensure that you are not violating any of the expectations of the language with which you are interfacing. For example, even though Java may not be susceptible to buffer overflows, providing a large argument in a call to native code might trigger an overflow.
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Implementation
Directly convert your input type into the expected data type, such as using a conversion function that translates a string into a number. After converting to the expected data type, ensure that the input's values fall within the expected range of allowable values and that multi-field consistencies are maintained.
Source: MITRE CWE-20
160 results · Clear filters · Feed
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High 7.5
Improper Input Validation in Apache Solr
Apache Solr 5.0.0 to Apache Solr 8.3.1 are vulnerable to a Remote Code Execution through the VelocityResponseWriter. A Velocity template can be provided through Velocity templates in a configset `velocity/` directory or as a parameter. A user defined configse…
KEV Nov 3, 2021 -
High 7.7
Cisco Wireless LAN Controller HTTP Parsing Engine Denial of Service Vulnerability
A vulnerability in the web interface of Cisco Wireless LAN Controller Software could allow a low-privileged, authenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability exists due to a failure of the HT…
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High 7.2
Improper Input Validation in Centreon Web
Centreon Web before 2.8.30, 18.10.x before 18.10.8, 19.04.x before 19.04.5 and 19.10.x before 19.10.2 allows Remote Code Execution by an administrator who can modify Macro Expression location settings. CVE-2019-16405 and CVE-2019-17501 are similar to one anot…
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High 7.2
Cisco Integrated Management Controller Supervisor, Cisco UCS Director, and Cisco UCS Director Express for Big Data Command Injection Vulnerability
A vulnerability in the web-based management interface of Cisco Integrated Management Controller (IMC) Supervisor, Cisco UCS Director, and Cisco UCS Director Express for Big Data could allow an authenticated, remote attacker to execute arbitrary commands on th…
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High 7.2
Cisco Small Business 220 Series Smart Switches Command Injection Vulnerability
A vulnerability in the web management interface of Cisco Small Business 220 Series Smart Switches could allow an authenticated, remote attacker to perform a command injection attack. The vulnerability is due to insufficient validation of user-supplied input. …
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High 8.8
A remote code execution vulnerability exists in Microsoft SQL Server when it incorrectly handles processing of internal…
KEV Aug 26, 2026 -
High 8.8
Cisco Prime Infrastructure and Evolved Programmable Network Manager Remote Code Execution Vulnerabilities
A vulnerability in the web-based management interface of Cisco Prime Infrastructure (PI) and Cisco Evolved Programmable Network (EPN) Manager could allow an authenticated, remote attacker to execute code with root-level privileges on the underlying operating …
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High 7.5CVE-2019-10742 Public exploit
Denial of Service in axios
Axios up to and including 0.18.0 allows attackers to cause a denial of service (application crash) by continuing to accepting content after maxContentLength is exceeded.
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High 7.8CVE-2019-11687 Public exploit
An issue was discovered in the DICOM Part 10 File Format in the NEMA DICOM Standard 1995 through 2019b and continuing i…
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High 7.4CVE-2019-1749 Public exploit
Cisco Aggregation Services Router 900 Route Switch Processor 3 OSPFv2 Denial of Service Vulnerability
A vulnerability in the ingress traffic validation of Cisco IOS XE Software for Cisco Aggregation Services Router (ASR) 900 Route Switch Processor 3 (RSP3) could allow an unauthenticated, adjacent attacker to trigger a reload of an affected device, resulting i…
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High 7.5CVE-2019-6690 Public exploit
Improper Input Validation python-gnupg
python-gnupg 0.4.3 allows context-dependent attackers to trick gnupg to decrypt other ciphertext than intended. To perform the attack, the passphrase to gnupg must be controlled by the adversary and the ciphertext should be trusted. Related to a "CWE-20: Impr…
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High 7.2
Cisco Small Business RV320 and RV325 Routers Command Injection Vulnerability
A vulnerability in the web-based management interface of Cisco Small Business RV320 and RV325 Dual Gigabit WAN VPN Routers could allow an authenticated, remote attacker with administrative privileges on an affected device to execute arbitrary commands. The vu…
KEV Mar 3, 2022 -
High 8.1
Apache Struts vulnerable to remote command execution (RCE) due to improper input validation
Apache Struts versions 2.3 to 2.3.34 and 2.5 to 2.5.16 suffer from possible Remote Code Execution when alwaysSelectFullNamespace is true (either by user or a plugin like Convention Plugin) and then: results are used with no namespace and in same time, its upp…
KEV Nov 3, 2021 -
High 8.8
A remote code execution vulnerability exists when the Windows Shell does not properly validate file paths, aka "Windows…
KEV Mar 25, 2022 -
High 7.5CVE-2018-10920 Public exploit
Improper input validation bug in DNS resolver component of Knot Resolver before 2.4.1 allows remote attacker to poison …
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High 7.5
Improper Input Validation in Jenkins
A arbitrary file read vulnerability exists in Jenkins 2.132 and earlier, 2.121.1 and earlier in the Stapler web framework's org/kohsuke/stapler/Stapler.java that allows attackers to send crafted HTTP requests returning the contents of any file on the Jenkins …
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High —
High severity vulnerability that affects org.apache.cxf.fediz:fediz-jetty8, org.apache.cxf.fediz:fediz-jetty9, org.apache.cxf.fediz:fediz-spring, org.apache.cxf.fediz:fediz-spring2, and org.apache.cxf.fediz:fediz-spring3
Versions of Apache CXF Fediz prior to 1.4.4 do not fully disable Document Type Declarations (DTDs) when either parsing the Identity Provider response in the application plugins, or in the Identity Provider itself when parsing certain XML-based parameters.
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High 7.5
A vulnerability in the web interface of the Cisco Adaptive Security Appliance (ASA) could allow an unauthenticated, rem…
KEV Nov 3, 2021 -
High 8.8
Improper Input Validation in Datomic
H2 1.4.197, as used in Datomic before 0.9.5697 and other products, allows remote code execution because CREATE ALIAS can execute arbitrary Java code. NOTE: the vendor's position is "h2 is not designed to be run outside of a secure environment."
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High 7.5
A vulnerability in the Smart Install feature of Cisco IOS Software and Cisco IOS XE Software could allow an unauthentic…
KEV Nov 3, 2021 -
High 7.2
High severity vulnerability that affects org.apache.syncope:syncope-core
An administrator with report and template entitlements in Apache Syncope 1.2.x before 1.2.11, 2.0.x before 2.0.8, and unsupported releases 1.0.x and 1.1.x which may be also affected, can use XSL Transformations (XSLT) to perform malicious operations, includin…
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High 8.8CVE-2017-15879 Public exploit
Keystone is vulnerable to CSV injection
CSV Injection (aka Excel Macro Injection or Formula Injection) exists in admin/server/api/download.js and lib/list/getCSVData.js in KeystoneJS before 4.0.0-beta.7 via a value that is mishandled in a CSV export.
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High 7.5
RubyGems may allow a maliciously crafted gem to overwrite files
RubyGems version 2.6.12 and earlier fails to validate specification names, allowing a maliciously crafted gem to potentially overwrite any file on the filesystem.
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High 7.8
(1) IQVW32.sys before 1.3.1.0 and (2) IQVW64.sys before 1.3.1.0 in the Intel Ethernet diagnostics driver for Windows al…
KEV Feb 10, 2023 -
High 8.8
DNN (aka DotNetNuke) has Remote Code Execution via a cookie
DNN (aka DotNetNuke) before 9.1.1 has Remote Code Execution via a cookie, aka "2017-08 (Critical) Possible remote code execution on DNN sites."
KEV Nov 3, 2021 -
High 7.1
Improper Input Validation in Apache Tomcat
The code in Apache Tomcat 9.0.0.M1 to 9.0.0.M11, 8.5.0 to 8.5.6, 8.0.0.RC1 to 8.0.38, 7.0.0 to 7.0.72, and 6.0.0 to 6.0.47 that parsed the HTTP request line permitted invalid characters. This could be exploited, in conjunction with a proxy that also permitted…
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High 8.1
The SMBv1 server in Microsoft Windows Vista SP2; Windows Server 2008 SP2 and R2 SP1; Windows 7 SP1; Windows 8.1; Window…
KEV Apr 6, 2022 -
High 7.5CVE-2016-4793 Public exploit
CakePHP allows remote attackers to spoof their IP
The clientIp function in CakePHP 3.2.4 and earlier allows remote attackers to spoof their IP via the CLIENT-IP HTTP header.
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High 8.4
The (1) EPHEMERAL, (2) HTTPS, (3) MVG, (4) MSL, (5) TEXT, (6) SHOW, (7) WIN, and (8) PLT coders in ImageMagick before 6…
KEV Sep 9, 2024 -
High 8.8
Jenkins allows Deserialization of Untrusted Data via an XML File
Multiple unspecified API endpoints in Jenkins before 1.650 and LTS before 1.642.2 allow remote authenticated users to execute arbitrary code via serialized data in an XML file, related to XStream and groovy.util.Expando.
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High 7.3
actionpack allows remote code execution via application's unrestricted use of render method
Action Pack in Ruby on Rails before 3.2.22.2, 4.x before 4.1.14.2, and 4.2.x before 4.2.5.2 allows remote attackers to execute arbitrary Ruby code by leveraging an application's unrestricted use of the render method.
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High 7.5
Siemens SIMATIC S7-300 CPU devices allow remote attackers to cause a denial of service (defect-mode transition) via cra…
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High —
Arbitrary code execution in Apache Commons BeanUtils
Apache Commons BeanUtils, as distributed in lib/commons-beanutils-1.8.0.jar in Apache Struts 1.x through 1.3.10 and in other products requiring commons-beanutils through 1.9.2, does not suppress the class property, which allows remote attackers to "manipulate…
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High 7.5
Commons FileUpload Denial of service vulnerability
MultipartStream.java in Apache Commons FileUpload before 1.3.1, as used in Apache Tomcat, JBoss Web, and other products, allows remote attackers to cause a denial of service (infinite loop and CPU consumption) via a crafted Content-Type header that bypasses a…
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High 8.8
The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the v6k and v7 ARM platforms do not…
KEV Sep 15, 2022 -
High —
Arbitrary file write in Apache Commons Fileupload
The DiskFileItem class in Apache Commons FileUpload, as used in Red Hat JBoss BRMS 5.3.1; JBoss Portal 4.3 CP07, 5.2.2, and 6.0.0; and Red Hat JBoss Web Server 1.0.2 allows remote attackers to write to arbitrary files via a NULL byte in a file name in a seria…
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High —
JSON gem has Improper Input Validation vulnerability
The JSON gem before 1.5.5, 1.6.x before 1.6.8, and 1.7.x before 1.7.7 for Ruby allows remote attackers to cause a denial of service (resource consumption) or bypass the mass assignment protection mechanism via a crafted JSON document that triggers the creatio…
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High —
actionpack Improper Input Validation vulnerability
active_support/core_ext/hash/conversions.rb in Ruby on Rails before 2.3.15, 3.0.x before 3.0.19, 3.1.x before 3.1.10, and 3.2.x before 3.2.11 does not properly restrict casts of string values, which allows remote attackers to conduct object-injection attacks …
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High 7.8
Unspecified vulnerability in Adobe Flash Player before 11.3.300.271 on Windows and Mac OS X and before 11.2.202.238 on …
KEV Mar 3, 2022 -
High —
CakePHP allows remote attackers to modify internal Cake cache and execute arbitrary code
The _validatePost function in libs/controller/components/security.php in CakePHP 1.3.x through 1.3.5 and 1.2.8 allows remote attackers to modify the internal Cake cache and execute arbitrary code via a crafted data[_Token][fields] value that is processed by t…