Weakness (CWE)
CWE-176: Improper Handling of Unicode Encoding
The product does not properly handle when an input contains Unicode encoding.
How to prevent it (3 mitigations)
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Architecture and Design
Avoid making decisions based on names of resources (e.g. files) if those resources can have alternate names.
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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-176
44 results · Feed
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High 7.1
SD JWT JS: Tampered disclosures silently dropped instead of rejected
SD JWT JS is a JavaScript implementation of the Selective Disclosure JWT (SD-JWT) specification. In version 0.19.0 and earlier, `@sd-jwt/decode`, also used by `@sd-jwt/core`, silently drops a tampered Disclosure whose digest no longer matches the Issuer-signe…
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Medium 5.3
Netty netty-tcnative before 2.0.84.Final SNI Hostname Spoofing via Modified UTF-8 Decoding
Netty netty-tcnative before 2.0.84.Final contains an SNI hostname spoofing vulnerability that allows remote unauthenticated clients to alter hostnames via JNI NewStringUTF decoding. Attackers can send overlong encodings like 0xC0 0x80 in the ClientHello serve…
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Medium 5.3
Vyper through 0.5.0b1 Literal Value Substitution via Multi-byte Characters
Vyper 0.1.0b1 before 0.1.0b12, 0.1.0b14, and 0.4.1 through 0.5.0b1 mix character-based line offsets with Python's UTF-8 byte col_offset values in vyper/ast/parse.py, so multi-byte characters shift the source slices used to reconstruct later numeric literals. …
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High 7.5
Cpanel::JSON::XS versions from 4.43 before 4.80 for Perl misorder byte-string keys during canonical encoding in utf16_cmp
Cpanel::JSON::XS versions from 4.43 before 4.80 for Perl misorder byte-string keys during canonical encoding in utf16_cmp. canonical sorts keys by UTF-16 code units. When any key in a hash is UTF-8 flagged, every key is decoded as UTF-8 for the comparison, in…
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Medium 6.5
Cpanel::JSON::XS versions from 4.33 before 4.80 for Perl miss duplicate non-ASCII bare keys, allowing type confusion under dupkeys_as_arrayref in decode_hv
Cpanel::JSON::XS versions from 4.33 before 4.80 for Perl miss duplicate non-ASCII bare keys, allowing type confusion under dupkeys_as_arrayref in decode_hv. With allow_barekey, which relaxed enables, a bare key containing a non-ASCII byte is stored as UTF-8 b…
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High 7.5
MOVEit Transfer Email MFA Bypass
Improper handling of unicode encoding vulnerability in Progress MOVEit Transfer. This issue affects MOVEit Transfer: before 2025.1.6 and from 2026.0.0 before 2026.0.4.
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Medium 5.3
Apache log4net: Unencodable content discards a whole SmtpPickupDirAppender batch
Improper Handling of Unicode Encoding vulnerability in the SmtpPickupDirAppender of Apache log4net. Content that the mail file writer cannot encode, such as an unpaired UTF-16 surrogate, made the write throw. Every buffered event in the batch was discarded, n…
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Medium 5.4
Net::Whois::Raw versions before 2.99044 for Perl ship a pwhois command-line tool that queries WHOIS for the wrong domain for unicode domain names
Net::Whois::Raw versions before 2.99044 for Perl ship a pwhois command-line tool that queries WHOIS for the wrong domain for unicode domain names. pwhois encodes each non-ASCII label directly using Net::IDN::Punycode and prepends xn--. Apart from lowercasing …
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Medium 5.3
Fireware OS Improper Authorization in Access Portal Reverse Proxy
An improper authorization vulnerability in Fireware OS's Access Portal reverse proxy allows an authenticated, low-privileged Access Portal user to access other web applications they are not authorized for by sending a specially crafted request for a different…
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High 7.5
Expat before 2.8.5 Malformed UTF-16 Acceptance via Unchecked Surrogate
Expat before 2.8.5 fails to validate that a high surrogate in UTF-16 input is followed by a low surrogate, allowing malformed UTF-16 sequences to be accepted. Attackers can supply UTF-16 encoded XML containing lone high surrogates that consume the following c…
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Medium 6.5
uri-js through 4.4.1 Improper UTF-8 Decoding via pctDecChars
uri-js through 4.4.1 contains an improper UTF-8 decoding vulnerability in pctDecChars() that decodes invalid and overlong percent-encoded sequences into ASCII metacharacters. Attackers can craft percent-encoded payloads to bypass platform decoder validation a…
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Medium 5.1
OpenTelemetry-Go: UTF-8 replacement rune bypasses attribute length truncation
OpenTelemetry-Go is the Go implementation of OpenTelemetry. From version 1.10.0 until 1.33.0, the sdk/trace/span.go attribute truncation path can fail to enforce AttributeValueLengthLimit for string and string-slice attributes containing the valid Unicode rep…
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Medium 5.5
Unicode normalization mismatch in go-slug ignore pattern matching may bypass intended file exclusions
HashiCorp go-slug 0.4.0 through 0.18.2 could allow a local attacker to bypass .terraformignore exclusions and cause sensitive files to be included in Terraform slug uploads due to improper handling of Unicode normalization during path matching.
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Medium 6.1
setuptools: MANIFEST.in exclusion bypass in sdist via Unicode normalization collision (NFC/NFD) on macOS APFS/HFS+
setuptools is a package that allows users to download, build, install, upgrade, and uninstall Python packages. Prior to 83.0.0, FileList applied MANIFEST.in exclude, global-exclude, recursive-exclude, and prune directives by matching compiled glob patterns ag…
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High 7.7
A flaw in Node.js TLS hostname handling can cause Node.js unicode dot separator handling can lead to tls wildcard-depth…
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High 8.1
Caddy: Unsafe Unicode Handling in FastCGI splitPos Allows Execution of Non-PHP Files
Caddy is an extensible server platform that uses TLS by default. From 2.7.0 until 2.11.3, the FastCGI transport's splitPos() in modules/caddyhttp/reverseproxy/fastcgi/fastcgi.go misuses golang.org/x/text/search with search.IgnoreCase when the request path con…
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High 7.3
Deno Permission Bypass via Unicode Normalization Mismatch on macOS (APFS)
Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.7.14, Deno's permission system enforces filesystem and execution restrictions by comparing the requested path against the path supplied to --deny-read, --deny-write, --deny-run, or --deny-f…
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High 8.1
FrankenPHP: Unsafe Unicode Handling in CGI Path Splitting Allows Execution of Non-PHP Files
FrankenPHP is a modern application server for PHP. From version 1.11.2 to before version 1.12.3, the splitPos() function in cgi.go misuses golang.org/x/text/search with search.IgnoreCase when the request path contains a non-ASCII byte. Two distinct flaws in t…
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Critical 9.8
SQLite sqldiff remote code execution via argument injection
SQLite 'sqldiff.exe' does not securely handle the way the Microsoft Windows C runtime converts Unicode characters to ANSI codepages. An attacker could use the '-L' option to load an arbitrary DLL with a crafted command line argument string that results in com…
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Medium 5.3
protobufjs: Overlong UTF-8 decoding
protobufjs compiles protobuf definitions into JavaScript (JS) functions. Prior to 7.5.6 and 8.0.2, protobufjs includes a minimal UTF-8 decoder that accepted overlong UTF-8 byte sequences and decoded them to their canonical characters instead of replacing them…
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High 7.5
Text::Minify::XS versions from 0.3.0 before 0.7.8 for Perl have heap overflow when processing some malformed UTF-8 characters
Text::Minify::XS versions from 0.3.0 before 0.7.8 for Perl have a heap overflow when processing some malformed UTF-8 characters. The minify functions mishandled some malformed UTF-8 characters, leading to heap corruption. Note that the minify_utf8 function is…
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Low 3.3
uutils coreutils split Local Data Integrity Issue via Lossy Filename Encoding
A logic error in the split utility of uutils coreutils causes the corruption of output filenames when provided with non-UTF-8 prefix or suffix inputs. The implementation utilizes to_string_lossy() when constructing chunk filenames, which automatically rewrite…
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Low 3.3
uutils coreutils ln Local Denial of Service via Improper Handling of Non-UTF-8 Filenames
A logic error in the ln utility of uutils coreutils causes the program to reject source paths containing non-UTF-8 filename bytes when using target-directory forms (e.g., ln SOURCE... DIRECTORY). While GNU ln treats filenames as raw bytes and creates the link…
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Low 3.3
uutils coreutils comm Silent Data Corruption via Lossy UTF-8 Normalization
The comm utility in uutils coreutils silently corrupts data by performing lossy UTF-8 conversion on all output lines. The implementation uses String::from_utf8_lossy(), which replaces invalid UTF-8 byte sequences with the Unicode replacement character (U+FFFD…
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Medium 6.6
Improper Input Validation during User Account Creation in Splunk Enterprise
In Splunk Enterprise versions below 10.2.2, 10.0.5, 9.4.10, and 9.3.11, and Splunk Cloud Platform versions below 10.4.2603.0, 10.3.2512.6, 10.2.2510.10, 10.1.2507.20, 10.0.2503.13, and 9.3.2411.127, a user who holds a role that contains the high-privilege cap…
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High 7.2
Improper handling of Unicode encoding in SonicWall SMA1000 series appliances allows a remote authenticated SSLVPN user …
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Medium 6.6
Improper handling of Unicode encoding in SonicWall SMA1000 series appliances allows a remote authenticated SSLVPN admin…
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Critical 9.8
XML::Parser versions through 2.45 for Perl could overflow the pre-allocated buffer size cause a heap corruption (double free or corruption) and crashes
XML::Parser versions through 2.45 for Perl could overflow the pre-allocated buffer size cause a heap corruption (double free or corruption) and crashes. A :utf8 PerlIO layer, parse_stream() in Expat.xs could overflow the XML input buffer because Perl's read()…
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Medium —
OpenClaw: Unicode canonicalization drift in node metadata policy classification could broaden node allowlists
### Summary A paired node could supply Unicode-confusable `platform` or `deviceFamily` metadata that passed metadata pinning but classified differently for command policy resolution, broadening default node command allowlists. ### Impact This is a policy-bypa…
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Medium 6.5
FileStore key canonicalization collisions allow response cache mixup/poisoning (ASCII ord + Unicode NFKD)
Litestar is an Asynchronous Server Gateway Interface (ASGI) framework. Prior to 2.20.0, FileStore maps cache keys to filenames using Unicode NFKD normalization and ord() substitution without separators, creating key collisions. When FileStore is used as respo…
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High 8.8
node-tar has Race Condition in Path Reservations via Unicode Ligature Collisions on macOS APFS
node-tar,a Tar for Node.js, has a race condition vulnerability in versions up to and including 7.5.3. This is due to an incomplete handling of Unicode path collisions in the `path-reservations` system. On case-insensitive or normalization-insensitive filesyst…
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Medium 5.4
HackerOne community member Kassem S.(kassem_s94) has reported that username handling in Revive Adserver was still vulne…
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Medium 5.3
DNN's CKEditor File Uploader functionality vulnerable through Unicode obfuscation
DNN (formerly DotNetNuke) is an open-source web content management platform (CMS) in the Microsoft ecosystem. Prior to version 10.1.0, the CKEditor file upload endpoint has insufficient sanitization for filenames allowing probing network endpoints. A speciall…
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High 7.3
In shouldHideDocument of ExternalStorageProvider.java, there is a possible bypass of a file path filter designed to pre…
KEV Nov 7, 2024 -
Medium 6.3
XZ Utils on Microsoft Windows platform are vulnerable to argument injection
XZ Utils provide a general-purpose data-compression library plus command-line tools. When built for native Windows (MinGW-w64 or MSVC), the command line tools from XZ Utils 5.6.2 and older have a command line argument injection vulnerability. If a command lin…
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Medium 5.8
Unicode "best fit" argument injection
In versions of Helix Core prior to 2024.1 Patch 2 (2024.1/2655224) a Windows ANSI API Unicode "best fit" argument injection was identified.
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Unscored —
Some Microsoft technologies as used in Windows 8 through 11 allow a temporary client-side performance degradation durin…
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Critical 9.6
Zoom Desktop Client for Windows, Zoom VDI Client for Windows, and Zoom Meeting SDK for Windows - Improper Input Validation
Improper input validation in Zoom Desktop Client for Windows, Zoom VDI Client for Windows, and Zoom Meeting SDK for Windows may allow an unauthenticated user to conduct an escalation of privilege via network access.
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Medium 5.3
ewen-lbh/ffcss late-Unicode normalization vulnerability
ffcss is a CLI interface to apply and configure Firefox CSS themes. Prior to 0.2.0, the function `lookupPreprocess()` is meant to apply some transformations to a string by disabling characters in the regex `[-_ .]`. However, due to the use of late Unicode nor…
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Medium 5.3
Late-Unicode normalization vulnerability in SHIRASAGI
SHIRASAGI is a Content Management System. Prior to version 1.18.0, SHIRASAGI is vulnerable to a Post-Unicode normalization issue. This happens when a logical validation or a security check is performed before a Unicode normalization. The Unicode character equ…