CWE-190: Integer Overflow vulnerabilities

UltraVNC viewer through 1.8.2.2 contains an integer overflow leading to a heap buffer overflow in the RFB protocol failure-response parsing path. In vncviewer/ClientConnection.cpp, the 4-byte network-supplied reasonLen field (type CARD32) is passed as reasonLen+1 to CheckBufferSize(). Because both operands are unsigned 32-bit, a reasonLen of 0xFFFFFFFF overflows to 0, causing CheckBufferSize to allocate only 256 bytes. The subsequent ReadString(m_netbuf, reasonLen) call then performs ReadExact for the original 4 GiB length into that 256-byte heap buffer. This overflow is reachable via rfbConnFailed (auth-scheme negotiation) and rfbVncAuthFailed (post-handshake) message types without successful authentication. A malicious VNC server, or any man-in-the-middle on the RFB stream, can trigger this condition when the victim viewer connects, potentially resulting in remote code execution as the user running the viewer. The crash was confirmed with AddressSanitizer on a portable reproduction harness (heap-buffer-overflow WRITE at offset 256).

UltraVNC repeater through 1.8.2.2 contains an integer overflow in the HTTP request logging path. In repeater/webgui/settings.c:336, the win_log() function allocates list nodes via malloc(sizeof(struct LIST) + strlen(line)), where line is derived from HTTP request URIs. If strlen(line) is sufficiently large, the addition overflows to a value smaller than sizeof(struct LIST), causing a heap allocation smaller than required. The subsequent strcpy of the full string into the undersized allocation produces a heap buffer overflow. In the current implementation this overflow is bounded by the HTTP receive buffer size (WI_RXBUFSIZE = 153600 bytes, well below SIZE_MAX on 32-bit builds), limiting practical exploitability to a partial heap write. A remote unauthenticated attacker can trigger the theoretical overflow path by sending a maximally-sized URI in an HTTP request to the repeater HTTP port.

Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. In versions prior to 3.17.2, Oj.load is vulnerable to heap corruption when parsing a JSON string longer than 2 GB. An integer overflow in buf_append_string (buf.h:61) converts the string length to a large negative size_t, causing memcpy to copy an astronomically large amount of data out of bounds. This crashes the process and can corrupt adjacent heap memory. The issue has been fixed in version 3.17.2.

CVE-2026-54900 is an integer overflow vulnerability in the Oj Ruby gem used for JSON parsing and object marshalling. Versions prior to 3.17.2 are affected when a JSON object key is exactly 65,535 bytes long, causing heap corruption and process crashes due to a negative size passed to memcpy. The issue is fixed in version 3.17.2.

ImageMagick versions before 7.1.2-22 have a vulnerability in binomial kernel processing where supplying a large binomial kernel value can cause an integer overflow leading to a division by zero and application crash. This results in a denial of service condition.

A flaw in Node.js WebCrypto implementation can crash the process if the input of `subtle.encrypt()` is a multiple of 2GiB. This vulnerability affects all supported release lines: **Node.js 22**, **Node.js 24**, and **Node.js 26**.

jq is a command-line JSON processor. Prior to 1.8.2, on 32bit system, jvp_string_append has a chance of integer/multiple overflowing and then causing a massive buffer overrun. This vulnerability is fixed in 1.8.2.

Nokogiri is an open source XML and HTML library for the Ruby programming language. Prior to 1.19.4, Nokogiri::XML::NodeSet#[] (and its alias #slice) checked the requested index against the node set's bounds using a 32-bit-truncated copy of the index. A large negative index could pass the check and then be used at full width, reading outside the node set's storage. On CRuby this is an out-of-bounds read that typically crashes the process; on JRuby it is not memory-unsafe but returns an incorrect node. This vulnerability is fixed in 1.19.4.

If NSD is configured as secondary for a zone, the primary of that zone can crash NSD with an AXFR containing a DNS message with a special crafted SVCB RR with an rdata size of 65512, that let's an (uint16_t) variable that is used to allocate space needed for the RR wrap (because total size > 65535), causing a heap overflow. The attacker can perform a controlled (RCE class) head write of up to 65509 bytes

xmlwf in libexpat before 2.8.2 has an integer overflow in resolveSystemId.

xmlwf in libexpat before 2.8.2 has an integer overflow for the output filename when -d outputDir is used.

xmlwf in libexpat before 2.8.2 has an integer overflow in endDoctypeDecl via NOTATION declarations.

libexpat before 2.8.2 has an integer overflow in copyString.

libexpat before 2.8.2 has an integer overflow in doProlog that is related to storeEntityValue and entity textLen.

libexpat before 2.8.2 has an integer overflow in XML_ParseBuffer because it lacked a check that was present in XML_Parse.

libexpat before 2.8.2 has an integer overflow in getAttributeId.

libexpat before 2.8.2 has an integer overflow in addBinding.

libexpat before 2.8.2 has an integer overflow in storeAtts.

libde265 is an open source implementation of the h.265 video codec. Prior to version 1.1.0, a crafted H.265 bitstream with large SPS dimensions and 16-bit bit depth causes a signed integer overflow in `de265_image_get_buffer()` (`libde265/image.cc:128`). The overflow wraps the plane allocation size to a small value (~1 KB), but the subsequent `fill_image()` call computes the real size using `size_t`, writing ~4 GB into the undersized heap buffer. Version 1.1.0 patches the issue.

An integer overflow or wraparound vulnerability exists in the EtherNet/IP function of Mitsubishi Electric MELSEC iQ-F Series FX5-EIP EtherNet/IP module FX5-EIP versions 1.000 and prior. A remote attacker can exploit this by rapidly establishing many TCP connections, causing a denial-of-service (DoS) due to improper memory access from inconsistent internal connection management.