PT-2026-56489

Name of the Vulnerable Software and Affected Versions js-yaml versions 5.0.0 through 5.1.x Description When merge keys are enabled, the parser can consume quadratic CPU time while processing a document. This occurs when a chain of mappings uses merge keys where each mapping merges the previous on...

PYSEC-2026-2022 phi4mm: Quadratic Time Complexity in Input Token Processing​ leads to denial of service

Summary A critical performance vulnerability has been identified in the input preprocessing logic of the multimodal tokenizer. The code dynamically replaces placeholder tokens e.g., , with repeated tokens based on precomputed lengths. Due to ​​inefficient list concatenation operations​​, the...

ruby: net-imap: Net::IMAP: Denial of Service via crafted IMAP responses

A flaw was found in Net::IMAP, a Ruby library implementing the Internet Message Access Protocol IMAP client functionality. A hostile server can exploit a quadratic time complexity issue in the Net::IMAP::ResponseReader when processing large responses containing numerous string literals. This can...

ruby: net-imap: Net::IMAP: Denial of Service via crafted IMAP responses

A flaw was found in Net::IMAP, a Ruby library implementing the Internet Message Access Protocol IMAP client functionality. A hostile server can exploit a quadratic time complexity issue in the Net::IMAP::ResponseReader when processing large responses containing numerous string literals. This can...

js-yaml: js-yaml: Denial of Service via quadratic CPU time parsing with merge keys

A flaw was found in js-yaml, a JavaScript YAML parser and dumper. When merge keys are enabled, a remote attacker could exploit this vulnerability by crafting a YAML document where a chain of mappings uses merge keys, each merging the previous one. This can lead to a significant increase in CPU ti...

js-yaml: js-yaml: Denial of Service via quadratic CPU time parsing with merge keys

A flaw was found in js-yaml, a JavaScript YAML parser and dumper. When merge keys are enabled, a remote attacker could exploit this vulnerability by crafting a YAML document where a chain of mappings uses merge keys, each merging the previous one. This can lead to a significant increase in CPU ti...

ruby: net-imap: Net::IMAP: Denial of Service via crafted IMAP responses

A flaw was found in Net::IMAP, a Ruby library implementing the Internet Message Access Protocol IMAP client functionality. A hostile server can exploit a quadratic time complexity issue in the Net::IMAP::ResponseReader when processing large responses containing numerous string literals. This can...

CVE-2026-53433

A flaw was found in fzf, a command-line fuzzy finder. This vulnerability allows a remote attacker to cause a Denial of Service DoS by sending a crafted POST request with many small segments to the --listen mode. The inefficient HTTP body processing, which uses repeated string concatenation, leads...

ruby: net-imap: Net::IMAP: Denial of Service via crafted IMAP responses

A flaw was found in Net::IMAP, a Ruby library implementing the Internet Message Access Protocol IMAP client functionality. A hostile server can exploit a quadratic time complexity issue in the Net::IMAP::ResponseReader when processing large responses containing numerous string literals. This can...

CVE-2026-53433

fzf is vulnerable to a Denial of Service DoS due to inefficient HTTP body processing in the --listen mode due to inefficient HTTP body processing using repeated string concatenation, resulting in quadratic time complexity On². A crafted POST request with many small segments can trigger excessive...

Mistune: Potential DoS via quadratic-time parsing in parse_link_text

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CVE-2026-13311

shell-quote prior to 1.8.5 finalizes parsed tokens in parse using Array.prototype.concat as a reduce accumulator, which reallocates and copies the entire growing array on every iteration. As a result parse runs in On^2 time relative to the number of input tokens. An attacker who can supply an...

CVE-2026-13311 shell-quote parse() is quadratic in token count, enabling denial of service

shell-quote prior to 1.8.5 finalizes parsed tokens in parse using Array.prototype.concat as a reduce accumulator, which reallocates and copies the entire growing array on every iteration. As a result parse runs in On^2 time relative to the number of input tokens. An attacker who can supply an...

CVE-2026-49851

Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, Mistune is vulnerable to a CPU exhaustion DoS due to superlinear approximately On² behavior in parselinktext. When parsing Markdown containing many consecutive characters, parselinktext repeatedly scans the input usin...

CVE-2026-49851

Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, Mistune is vulnerable to a CPU exhaustion DoS due to superlinear approximately On² behavior in parselinktext. When parsing Markdown containing many consecutive characters, parselinktext repeatedly scans the input usin...

CVE-2026-49851 Mistune: Potential DoS via quadratic-time parsing in parse_link_text

Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, Mistune is vulnerable to a CPU exhaustion DoS due to superlinear approximately On² behavior in parselinktext. When parsing Markdown containing many consecutive characters, parselinktext repeatedly scans the input usin...

CVE-2026-49851 Mistune: Potential DoS via quadratic-time parsing in parse_link_text

Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, Mistune is vulnerable to a CPU exhaustion DoS due to superlinear approximately On² behavior in parselinktext. When parsing Markdown containing many consecutive characters, parselinktext repeatedly scans the input usin...

CVE-2026-49851

Mistune (Python Markdown parser) prior to 3.3.0 is vulnerable to CPU exhaustion DoS due to quadratic-time behavior in parse_link_text when parsing many consecutive '[' characters. The code repeatedly scans input with a regex inside a loop, yielding O(n^2) runtime on affected inputs and enabling a...

CVE-2026-54892 Plug: quadratic-time decoding of nested query/body parameters enables denial of service

Inefficient algorithmic complexity in Plug's nested-parameter decoder allows an unauthenticated remote attacker to cause denial of service. Plug.Conn.Query.decode/4 and Plug.Conn.Query.decodeeach/2 parse query strings and application/x-www-form-urlencoded request bodies. When a key contains many...

CVE-2026-53539 Python-Multipart: Quadratic-time querystring parsing with semicolon separators causes CPU denial of service

Python-Multipart is a streaming multipart parser for Python. Prior to 0.0.30, when parsing application/x-www-form-urlencoded bodies, QuerystringParser located the field separator with a two step lookup: it first scanned the entire remaining buffer for &, and only when no & existed anywhere ahead...