Weakness (CWE)
CWE-1286: Improper Validation of Syntactic Correctness of Input
The product receives input that is expected to be well-formed - i.e., to comply with a certain syntax - but it does not validate or incorrectly validates that the input complies with the syntax.
How to prevent it (1 mitigation)
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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.
Source: MITRE CWE-1286
47 results · Clear filters · Feed
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Medium 4.8
Rack: Rack::Request#host_with_port (and #base_url / #url) return the raw invalid Host header — incomplete fix of CVE-2026-34835
Rack is a modular Ruby web server interface. From 3.0 until 3.1.23 and 3.2.8, Rack::Request#host_with_port, #base_url, and #url can return an attacker-controlled invalid authority from Host, X-Forwarded-Host, or Forwarded: host= verbatim. Applications without…
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Medium 6.7
In neuropilot, there is a possible out of bounds write due to a missing bounds check. This could lead to local escalati…
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Medium 6.9
Unvalidated HTTP/1 request-target authority lets a client choose conn.host and conn.port in Bandit
Improper Validation of Syntactic Correctness of Input vulnerability in mtrudel bandit allows an unauthenticated remote attacker to set conn.host and conn.port to values outside the RFC 3986 host grammar via the authority of an HTTP/1 absolute-form or authorit…
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Medium 5.3
RabbitMQ MQTT 5: inapplicable PUBLISH property disconnects matching subscribers
RabbitMQ is a messaging and streaming broker. From 3.13.0 until 3.13.19, 4.0.24, 4.1.15, 4.2.10, and 4.3.5, the MQTT 5 parser in deps/rabbitmq_mqtt/src/rabbit_mqtt_packet.erl accepts Request-Problem-Information on PUBLISH packets even though the property is v…
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Medium 5.3
Tink-go 2.8.0 Keyset Validation Bypass via NewHandleWithNoSecrets
Tink-go (tink-crypto/tink-go) through 2.8.0 contains an input-validation vulnerability where keyset.NewHandleWithNoSecrets() and ReadWithNoSecrets() skip the structural Validate() step before constructing a keyset.Handle, allowing malformed public or no-secre…
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Medium 6.5
Barco ClickShare CX-20 Gen2 Wallpaper Upload wallpaper improper validation of syntactic correctness of input
A vulnerability was determined in Barco ClickShare CX-20 Gen2 up to 02.26.00.0007. Affected by this issue is some unknown functionality of the file /wallpaper of the component Wallpaper Upload. This manipulation of the argument wallpaper causes improper valid…
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Medium 4.8
Http4s: Set-Cookie rendering does not escape attribute delimiters
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, ResponseCookie.render writes attacker-influenced name, content, domain, path, and extension values without neutralizing semicolons or control characters. An application that constr…
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Medium 6.9
xmldom: Parser silently accepts a not-well-formed end tag whose name is followed by a line break and trailing content
xmldom is a pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and XMLSerializer module. Prior to @xmldom/xmldom versions 0.8.15 and 0.9.12, and in xmldom version 0.6.0 and earlier, DOMParser.parseFromString() can silently accept an end tag s…
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Medium 6.3
Mastodon: SSRF Protection Bypass via IPv4-compatible IPv6 Addresses
Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.4.21, 4.5.14, 4.6.4, and 4.7.0-beta.1, PrivateAddressCheck.private_address? in app/lib/private_address_check.rb normalized IPv4-mapped IPv6 addresses but did not recognize …
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Medium 6.9
Denial-of-service vulnerability in M-Files Server
Denial-of-service vulnerability in M-Files Server versions before 26.5.16015.3 allows an authenticated admin user to cause the M-Files Server process to crash and fail to restart.
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Medium 5.8
Guzzle: Dot-Only Cookie Domains Match All Hosts in guzzlehttp/guzzle
Guzzle is an extensible PHP HTTP client. Prior to 7.12.1, CookieJar incorrectly accepts cookies with a dot-only Domain attribute and whitespace-padded variants. SetCookie::matchesDomain() removes leading dots from the cookie domain, normalizing dot-only value…
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Medium 6.5
Dräger SC Monitoring Devices DoS via Malformed Network Packet
Dräger SC Monitoring devices (SC 6002XL, SC 6802XL, SC 7000, SC 8000, SC 9000 XL) contain a denial-of-service vulnerability in all software versions that allows unauthenticated attackers to reboot the monitor by sending a malformed network packet. Attackers c…
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Medium 4.0
Dräger Atlan A350 1.00 <= 1.01 DoS via Medibus Interface
Dräger Atlan A350 versions 1.00 up to and including 1.01 contains an improper input handling vulnerability that allows attackers to cause a denial of service by sending specifically crafted non-Medibus-compliant data through the Medibus interface. Attackers c…
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Medium 4.0
Dräger Perseus A500 2.00-2.02 DoS via Medibus Interface
Dräger Perseus A500 software versions 2.00 through 2.02 contains an improper input handling vulnerability that allows external attackers to cause a denial of service by sending specifically crafted non-Medibus-compliant data through the Medibus interface. Att…
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Medium 4.0
XX-Net V5.16.6 WebSocket Frame Parsing Data Corruption via simple_http_server.py
XX-Net V5.16.6 contains a WebSocket frame parsing vulnerability in the WebSocket_receive_worker routine of simple_http_server.py that allows attackers to cause corrupted application data by sending unmasked WebSocket frames. The server unconditionally reads 4…
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Medium 4.8CVE-2026-34835 Public exploit
Rack: `Rack::Request` accepts invalid Host characters, enabling host allowlist bypass.
Rack is a modular Ruby web server interface. From versions 3.0.0.beta1 to before 3.1.21, and 3.2.0 to before 3.2.6, Rack::Request parses the Host header using an AUTHORITY regular expression that accepts characters not permitted in RFC-compliant hostnames, in…
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Medium 5.4
A vulnerability in the Lobby Ambassador web-based management API of Cisco IOS XE Software could allow an authenticated,…
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Medium 5.0
IBM QRadar SIEM Information Disclosure
IBM QRadar SIEM 7.5.0 through 7.5.0 Update Package 14 could allow an attacker with access to one tenant to access hostname data from another tenant's account.
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Medium 5.3
API - Insufficient Input Validation
Improper validation of API end-point in 2N Access Commander version 3.4.2 and prior allows attacker to bypass password policy for backup file encryption. This vulnerability can only be exploited after authenticating with administrator privileges.
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Medium 6.3
Uv: uv: specially crafted zip archives lead to arbitrary code execution due to parsing differentials
A flaw was found in uv. This vulnerability allows an attacker to execute malicious code during package resolution or installation via specially crafted ZIP (Zipped Information Package) archives that exploit parsing differentials, requiring user interaction to…
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Medium 6.5
Microsoft Exchange Server Spoofing Vulnerability
User interface (ui) misrepresentation of critical information in Microsoft Exchange Server allows an unauthorized attacker to perform spoofing over a network.
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Medium 6.9
Denial of Service condition in M-Files Server
Denial-of-service vulnerability in M-Files Server versions before 26.1.15632.3 allows an authenticated attacker with vault administrator privileges to crash the M-Files Server process by calling a vulnerable API endpoint.
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Medium 5.3
Weblate's over‑permissive webhook endpoint enables mass repository updates and component enumeration
Weblate is a web based localization tool. In versions prior to 5.15, it was possible to trigger repository updates for many repositories via a crafted webhook payload. Version 5.15 fixes the issue. As a workaround, disabling webhooks completely using ENABLE_H…
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Medium 4.9
IBM Planning Analytics Local information disclosure
IBM Planning Analytics Local 2.0.0 through 2.0.106 and 2.1.0 through 2.1.13 could allow a malicious privileged user to bypass the UI to gain unauthorized access to sensitive information due to the improper validation of input.
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Medium 5.3
github.com/nyaruka/phonenumbers Vulnerable to Improper Validation of Syntactic Correctness of Input
Versions of the package github.com/nyaruka/phonenumbers before 1.2.2 are vulnerable to Improper Validation of Syntactic Correctness of Input in the phonenumbers.Parse() function. An attacker can cause a panic by providing crafted input causing a "runtime erro…
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Medium 6.5
Asterisk remotely exploitable leak of RTP UDP ports and internal resources
Asterisk is an open source private branch exchange and telephony toolkit. Prior to versions 18.26.4 and 18.9-cert17, RTP UDP ports and internal resources can leak due to a lack of session termination. This could result in leaks and resource exhaustion. This i…
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Medium 5.3
Microsoft Exchange Server Spoofing Vulnerability
Improper validation of syntactic correctness of input in Microsoft Exchange Server allows an unauthorized attacker to perform spoofing over a network.
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Medium 6.0
F5OS-A/C CLI vulnerability
When running in Appliance mode, an authenticated attacker assigned the Administrator or Resource Administrator role may be able to bypass Appliance mode restrictions utilizing system diagnostics tcpdump command utility on a F5OS-C/A system. Note: Software ve…
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Medium 5.4
A vulnerability in the “Network Interfaces” functionality of the web application of ctrlX OS allows a remote authentica…
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Medium 6.5
A vulnerability in the “Network Interfaces” functionality of the web application of ctrlX OS allows a remote authentica…
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Medium 6.3
A vulnerability in the “Hosts” functionality of the web application of ctrlX OS allows a remote authenticated (low-priv…
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Medium 5.9
Westermo WeOS 5 through 5.23.0 allows a reboot via a malformed ESP packet.
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Medium 4.3
IBM App Connect Enterprise Certified Container denial of service
IBM App Connect Enterprise Certified Container 7.2, 8.0, 8.1, 8.2, 9.0, 9.1, 9.2, 10.0, 10.1, 11.0, 11.1, 11.2, 11.3, 11.4, 11.5, 11.6, 12.0, 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, and 12.8 could allow an authenticated user to cause a denial of service in …
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Medium 6.5
In Modem, there is a possible memory corruption due to incorrect error handling. This could lead to remote denial of se…
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Medium 6.5
A vulnerability has been identified in SIMATIC S7-1200 CPU 1211C AC/DC/Rly (6ES7211-1BE40-0XB0) (All versions < V4.7), …
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Medium 4.3
51l3nc3, member of the AXIS OS Bug Bounty Program, has found that the VAPIX API managedoverlayimages.cgi was vulnerable…
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Medium 4.9
Denial of Service in TYPO3 Bookmark Toolbar
TYPO3 before 13.3.1 allows denial of service (interface error) in the Bookmark Toolbar (ext:backend), exploitable by an administrator-level backend user account via manipulated data saved in the bookmark toolbar of the backend user interface. The fixed versio…
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Medium 6.5
51l3nc3, member of the AXIS OS Bug Bounty Program, has found that a Guard Tour VAPIX API parameter allowed the use of a…
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Medium 6.3
Improper IPv4 and IPv6 byte order storage in github.com/google/nftables
In https://github.com/google/nftables IP addresses were encoded in the wrong byte order, resulting in an nftables configuration which does not work as intended (might block or not block the desired addresses). This issue affects: https://pkg.go.dev/github.c…
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Medium 6.5
Improper input validation in the user management function of web interface in Aten PE6208 2.3.228 and 2.4.232 allows re…