Loop with Unreachable Exit Condition ('Infinite Loop')

HFS2 version 2.4.0 and earlier contains a denial of service vulnerability that allows unauthenticated attackers to cause a complete and persistent loss of availability by sending a single crafted request. Attackers can trigger a hung serving thread that enters a busy loop, rendering the entire file server unresponsive to all clients without self-recovery until an operator manually restarts the service.Show less

Integer overflow in the packet buffer growth logic in PgBouncer through 1.25.2 allows an unauthenticated remote attacker to cause a denial of service. Sufficiently large input makes the buffer size computation overflow, leaving the growth loop unable to terminate. Because PgBouncer serves all clients from a single process, this saturates a CPU core and stalls every pooled connection until the process is killed. Both unauthenticated and authenticated code paths can reach the overflow.Show less

radare2 is a UNIX-like reverse engineering framework and command-line toolset. Prior to 6.2.0, radare2's NE relocation fixup-chain parser was vulnerable because the NE relocation parser followed fixup chains without an active iteration limit or cycle detection. The vulnerability is triggered by opening a crafted NE executable whose in-bounds relocation entry points back to itself instead of reaching 0xffff. The parser repeatedly processed the same relocation and allocated another relocation object on each iteration. This can cause denial of service through continuous CPU and memory consumption. This issue is fixed in version 6.2.0.Show less

Net::IDN::Punycode versions before 2.590 for Perl hang, crash or return a wrong label via unvalidated malformed UTF-8 in encode_punycode. Neither backend checks that its input is well-formed UTF-8, so a string with the UTF-8 flag set over malformed bytes, as the :utf8 PerlIO layer produces from any malformed input, reaches the encoder unchecked. On perl 5.32 and later the XS backend reports a malformed sequence with a length of `(STRLEN)-1`, so the scan steps back one byte instead of forward and never ends. On earlier perls the XS returns a valid label for a different name. The pure-Perl backend runs a regex over the flagged string. Depending on the bytes, it aborts with SIGBUS on perl 5.28 and later, dies with a panic, or returns a wrong label. The documented conversion functions match the label against Unicode properties first and that match dies on such a string, so only a direct call to encode_punycode reaches the defect. The decoder is not affected. A direct caller encoding attacker-supplied bytes hangs, crashes or gets a label for a name the input never held.Show less

Pod::Text versions before 6.1.1 for Perl allow CPU and memory exhaustion formatting a POD document whose =over nesting drives the margin to the output width. Each =over adds its indent to the margin, which wrap() subtracts from the output width to get the space available for text. When that space reaches zero, the line-splitting substitution matches the empty string, and the loop consumes no input while appending the margin padding on every pass. Formatting an attacker-supplied POD document never returns, and the output grows until memory is exhausted.Show less

NanoMQ is an MQTT broker. Prior to 0.24.14, the NanoMQ client function nni_mqtt_msg_decode_unsubscribe() in nng/src/supplemental/mqtt/mqtt_codec.c does not handle a failed read_uint16() while counting topics in a malformed UNSUBSCRIBE packet. A zero-length topic followed by trailing data can leave buf.curpos unchanged while topic_count continues to increase, allowing a malicious MQTT broker to hang a connecting MQTT 3.1.1 client, consume CPU and memory, and repeatedly deny service when automatic reconnection is enabled. The broker-side nmq_unsubinfo_decode path is not affected. This issue is fixed in version 0.24.14.Show less

uri-js through 4.4.1 contains a denial of service vulnerability in the removeDotSegments function that loops infinitely when a path segment begins with Unicode line or paragraph separators. Attackers can trigger this by calling removeDotSegments directly or through normalize/resolve functions with IRI handling enabled, causing the Node.js event loop to block indefinitely until heap exhaustion.Show less

libheif is a HEIF and AVIF file format decoder and encoder. Prior to 1.23.2, crafted HEIF sequence timing and edit-list data can make Track::init_sample_timing_table() compute a logical m_num_output_samples value that exceeds the uint32_t counters used by Track_Visual::decode_next_image_sample() and Track::get_next_sample_raw_data(). The resulting comparison can never reach the oversized output count, causing non-terminating decode or raw-sample loops and bypassing max_sequence_frames. The same sequence path repeatedly calls Box_stts::get_sample_duration() and allocates Chunk::m_sample_ranges and Track::m_presentation_timeline outside MemoryHandle accounting, allowing severe CPU and memory exhaustion from a small file. This issue is fixed in version 1.23.2.Show less

`fulgur` converts untrusted HTML/CSS into PDF, commonly on a server that processes input supplied by many tenants. In versions prior to 0.19.0, a body-direct child whose CSS-resolved height greatly exceeds the page height was sliced into one fragment per page with no upper bound. This is fixed in version 0.19.0. A `MAX_PAGES` cap bounds the slice loop — halting it even for a `+inf` height — and non-finite layout heights are sanitized so they can no longer drive the loop. As a workaround, validate or constrain untrusted CSS (in particular `height` / `vh` on body-level elements) before passing HTML to fulgur.Show less

`fulgur` converts untrusted HTML/CSS into PDF, commonly on a server that processes input supplied by many tenants. In versions prior to 0.19.0, a body-direct child whose CSS-resolved height greatly exceeds the page height was sliced into one fragment per page with no upper bound. This is fixed in 0.19.0. A `MAX_PAGES` cap bounds the slice loop — halting it even for a `+inf` height — and non-finite layout heights are sanitized so they can no longer drive the loop. As a workaround, validate or constrain untrusted CSS (in particular `height` / `vh` on body-level elements) before passing HTML to fulgur.Show less

ExifReader is a JavaScript Exif information parser. Prior to 4.41.1, ExifReader parses attacker-controlled HEIC or AVIF ISO-BMFF files in getItems() within src/image-header-iso-bmff-iloc.js and trusts iloc itemCount and extentCount values while allocating an extent object for every nested-loop iteration. When offsetSize, lengthSize, baseOffsetSize, and indexSize are zero, the extent fields consume no input bytes and the buffer offset does not advance, but the parser can still allocate up to itemCount multiplied by extentCount objects without an allocation budget. A small malicious iloc box can therefore cause hundreds of megabytes of heap growth or exhaust system memory, terminating a Node.js process and denying service to web, desktop, or mobile applications that parse untrusted images. The zero field widths are valid ISO-BMFF values indicating absent fields, so the vulnerable parser must bound work rather than relying on offset advancement. The issue is fixed in version 4.41.1.Show less

A vulnerability in the system rate-limiting process for syslog message 419002 of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause high CPU utilization on an affected device, resulting in a denial of service (DoS) condition. This vulnerability is due to improper rate limiting for syslog message 419002. An attacker could exploit this vulnerability by sending a flood of TCP synchronization (SYN) packets to an affected device. A successful exploit could allow the attacker to cause high CPU utilization, resulting in performance degradation. Show less

AsyncSSH is a Python package which provides an asynchronous client and server implementation of the SSHv2 protocol on top of the Python asyncio framework. Prior to 2.24.0, _process_channel_open and _process_channel_open_confirmation in asyncssh/connection.py accept a peer-supplied send_pktsize value of zero. When channel data reaches SSHChannel._flush_send_buf in asyncssh/channel.py, the zero value causes each loop iteration to slice and remove zero bytes without reducing the send window, leaving the synchronous loop permanently true with no await point. A malicious SSH server can trigger the client path through SSH_MSG_CHANNEL_OPEN_CONFIRMATION before the first channel write, while an authenticated client can trigger the server path through SSH_MSG_CHANNEL_OPEN and freeze every current and future connection handled by the process. This vulnerability is fixed in 2.24.0.Show less

HAPI FHIR is a complete implementation of the HL7 FHIR standard for healthcare interoperability in Java. Prior to version 6.9.12, SHCParser in org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/elementmodel/SHCParser.java can enter an infinite loop while processing attacker-controlled Smart Health Card JWT content whose header contains zip: "DEF" and whose raw-DEFLATE payload is empty or truncated. SHCParser.decodeJWT() reaches SHCParser.inflate(), where Inflater.inflate() can return zero while Inflater.finished() remains false and Inflater.needsInput() is true. The loop also lacks an Inflater.needsDictionary() termination check, SHCParser.decompress() contains the same zero-progress pattern, and ResourceChecker.java can reach SHC parsing during file-format detection. A malformed validation request can pin a JVM worker thread indefinitely, and concurrent requests can exhaust all validation workers. This issue is fixed in version 6.9.12.Show less

react/http is an event-driven, streaming HTTP client and server implementation for ReactPHP. From 0.6.0 until 1.11.1, React\Http\Io\ChunkedDecoder could enter an infinite loop while processing a malformed Transfer-Encoding: chunked body because handleData required its buffer to shrink on every iteration. An incomplete terminal-chunk trailer without CRLF left the buffer unchanged after strpos returned false, and exactly two non-CRLF bytes after a completed non-terminal chunk bypassed both the error and wait guards. The affected decoder processes request bodies for React\Http\HttpServer and response bodies for React\Http\Browser, allowing a malicious client to freeze a server or a malicious or compromised server to freeze a client. A reverse proxy that normalizes inbound requests may protect the server direction but does not protect outbound Browser requests. This issue is fixed in version 1.11.1.Show less

Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, WebSocket FrameTranscoder.bodyLength rejects extended payload lengths above Integer.MAX_VALUE but permits negative 64-bit lengths. A remote client that completes a WebSocket handshake through an Ember server can send such a frame, causing the decoder to return an empty frame without advancing its input. The decode loop then runs indefinitely, pins a worker at full CPU, and grows an ArrayBuffer without bound, resulting in denial of service. This issue is fixed in versions 0.23.35 and 1.0.0-M47.Show less

FreeRDP versions before 3.31.0 contain an infinite-loop denial of service in the pool_decode_rect function when decoding AVC444 metablocks with more region rectangles than preallocated worker array size. A malicious RDP server can send crafted AVC444 graphics updates causing the threaded decode path to loop indefinitely, consuming CPU and preventing normal client operation.Show less

Converting crafted EUC_JISX0213 input to UCS-4 or the internal wide character encoding, for example with iconv, in the GNU C Library version 2.3 to 2.44 may result in the converter making no progress, causing the calling application to hang. Some EUC_JISX0213 sequences decode to two code points. If the output buffer has room for only the first one, the converter stores the second in the conversion state and returns E2BIG, but it never clears that pending character after emitting it on the next call. The converter then keeps emitting the pending character without consuming further input, so an application that retries the conversion loops forever. The input must be attacker controlled and the application must convert it with an output buffer small enough to split the two code points. Only the EUC_JISX0213 character set is affected, which is not commonly used. The related defect in SHIFT_JISX0213 converter is tracked separately as CVE-2026-77117.Show less

Converting crafted SHIFT_JISX0213 input to UCS-4 or the internal wide character encoding, for example with iconv, in the GNU C Library version 2.3 to 2.44 may result in the converter making no progress, causing the calling application to hang. Some SHIFT_JISX0213 sequences decode to two code points. If the output buffer has room for only the first one, the converter stores the second in the conversion state and returns E2BIG, but it never clears that pending character after emitting it on the next call. The converter then keeps emitting the pending character without consuming further input, so an application that retries the conversion loops forever. The input must be attacker controlled and the application must convert it with an output buffer small enough to split the two code points. Only the SHIFT_JISX0213 character set is affected, which is not commonly used. The related defect in the EUC_JISX0213 converter is tracked separately as CVE-2026-80489.Show less