Weakness (CWE)
CWE-158: Improper Neutralization of Null Byte or NUL Character
The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes NUL characters or null bytes when they are sent to a downstream component.
How to prevent it (3 mitigations)
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Developers should anticipate that null characters or null bytes will be injected/removed/manipulated in the input vectors of their product. Use an appropriate combination of denylists and allowlists to ensure only valid, expected and appropriate input is processed by the system.
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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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Implementation
Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked.
Source: MITRE CWE-158
14 results · Clear filters · Feed
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Medium 6.5
Mongoose: Heap OOB reads and null-byte bypass in mg_path_is_sane (util.c)
Mongoose is an embedded web server and network library. Prior to 7.22, mg_path_is_sane in src/util.c read path.buf[1] without first requiring path.len to be at least two and read s[2] when only two bytes remained. Unauthenticated remote requests reaching mg_h…
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Medium 5.3
socket.getaddrinfo() accepts embedded null bytes in host and port
socket.getaddrinfo() previously accepted null bytes within *host* and *port* parameters which can cause the values to be silently truncated.
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Medium 4.8
Botan: Python binding bcrypt APIs truncate passwords containing embedded NULs
Botan is a C++ cryptography library. From 1.11.22 until 3.13.0, Botan's Python binding converted Python strings containing U+0000 to const char* values without consistently rejecting the embedded NUL, causing bcrypt and check_bcrypt to process only the prefix…
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Medium 5.3
Apache log4net: NUL character truncates OutputDebugStringAppender records
Improper Neutralization of Null Byte or NUL Character vulnerability in the OutputDebugStringAppender of Apache log4net. A NUL character in logged content ended the debug output record at that point, so everything the layout rendered after it, including except…
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Medium 5.3
Apache log4net: NUL character truncates EventLogAppender records
Improper Neutralization of Null Byte or NUL Character vulnerability in the EventLogAppender of Apache log4net. A NUL character in logged content ended the Windows Event Log record at that point, so everything the layout rendered after it, including exception …
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Medium 6.0
Electron: shell.openPath path validation bypass via embedded null byte
Electron is a framework for writing cross-platform desktop applications using JavaScript, HTML and CSS. Prior to 39.8.6, 40.9.0, 41.1.1, and 42.0.0-beta.1, shell.openPath() did not reject paths containing embedded null bytes. Apps that perform string-only val…
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Medium 4.4
Envoy: Embedded NUL in TLS DNS SAN Truncation in the Default TLS Certificate Validator. (Auth Bypass)
Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.35.11, 1.36.7, 1.37.3, and 1.38.1, a structural flaw was identified in DefaultCertValidator::verifySubjectAltName where the extracted DNS SAN string is cast to a…
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Medium 4.4
jq: Embedded NUL in jq import paths causes local redaction-policy bypass and preserves sensitive fields in published artifacts
jq is a command-line JSON processor. In 1.8.1 and earlier, jq accepts embedded NUL bytes in import paths at the jq-language level, but later resolves those paths through C string operations during module and data-file lookup. This creates a mismatch between t…
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Medium 5.5
jq: Embedded NUL truncates top-level jq programs loaded with -f
jq is a command-line JSON processor. In 1.8.1 and earlier, Top-level jq programs loaded from a file with -f are truncated at the first embedded NUL byte on current upstream HEAD. A crafted filter file such as . followed by \x00 and arbitrary suffix compiles a…
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Medium 6.5
An attachment spoofing issue in WhatsApp for Windows prior to v2.3000.1032164386.258709 could have allowed maliciously …
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Medium 4.0
Out-of-bounds character read vulnerability in Bluetooth. Impact: Successful exploitation of this vulnerability may affe…
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Medium 6.8
Improper neutralization of null bytes may lead to buffer over-reads in MongoDB Server
An authorized user may trigger crashes or receive the contents of buffer over-reads of Server memory by issuing specially crafted requests that construct malformed BSON in the MongoDB Server. This issue affects MongoDB Server v5.0 versions prior to 5.0.30 , M…
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Medium 5.5
Xorg-x11-server: selinux unlabeled glx pbuffer
A flaw was found in the X.Org server. The GLX PBuffer code does not call the XACE hook when creating the buffer, leaving it unlabeled. When the client issues another request to access that resource (as with a GetGeometry) or when it creates another resource t…
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Medium 6.5
Improper neutralization of null byte leads to read overrun
A user authorized to perform database queries may trigger a read overrun and access arbitrary memory by issuing specially crafted queries. This issue affects MongoDB Server v4.4 versions prior to 4.4.1; MongoDB Server v4.2 versions prior to 4.2.9; MongoDB Ser…