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Vulnerability Database

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A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

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A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. Risk increases sharply when exploitation becomes reliable or widespread.

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Total vulnerabilities in the database

Tiptap: Quadratic ReDoS in block and inline Markdown attribute parsing — @tiptap / core

Summary

@tiptap/core contains two quadratic regular-expression denial-of-service paths in its default Markdown attribute parsers. Pandoc-style block attributes use two unanchored greedy expressions that rescan repeated __QUOTED_0 prefixes. Inline shortcode attributes use another unanchored greedy key expression that rescans a long word-character run when no equals sign follows.

The public createAtomBlockMarkdownSpec and createBlockMarkdownSpec helpers call the vulnerable Pandoc-style parser; createInlineMarkdownSpec calls the separately vulnerable shortcode parser. Using unmodified npm 3.29.2, a complete 20,508-byte atom-block token took approximately 1.40 seconds while an equal-length control took 0.29 ms. A complete 32,776-byte inline token took approximately 2.21 seconds while its equal-length control took 0.19 ms. Current repository main commit 5158212970344952dd9918b6a44bfb400d7fb6c1 retains both expressions.

Block attribute root cause

packages/core/src/utilities/markdown/attributeUtils.ts uses both matchAll and replace with /([a-zA-Z][\w-]*)\s*=\s*(__QUOTED_\d+__)/g. The candidate is '__QUOTED_0'.repeat(n) + '__QUOTED_0__'. There are no quotes, so the preceding replacement leaves it unchanged. At each Q, the greedy key-name expression consumes the remaining word-character run, the required equals sign fails, and the unanchored engine restarts at the next Q. This yields O(n^2) work, and the cleanup pass repeats it.

A complete public-API proof is:

import { createAtomBlockMarkdownSpec } from &#039;@tiptap/core&#039;
const tokenizer = createAtomBlockMarkdownSpec({ nodeName: &#039;probe&#039; }).markdownTokenizer
const attack = &#039;__QUOTED_0&#039;.repeat(2048) + &#039;__QUOTED_0__&#039;
const source = `:::probe {${attack}} :::\n`
const started = performance.now()
tokenizer.tokenize(source, [], {})
console.log(performance.now() - started)

Measured complete-tokenizer timings were 6.23, 23.12, 88.93, 369.10, and 1,400.17 ms at 1,308, 2,588, 5,148, 10,268, and 20,508 bytes. Equal-length controls took 0.07 to 0.29 ms. The directly exported parser took 5,645.71 ms at 40,972 bytes while its control took 0.64 ms.

Inline attribute root cause

packages/core/src/utilities/markdown/createInlineMarkdownSpec.ts uses /(\w+)=(?:"([^"]*)"|'([^']*)')/g. For a long word-character run without an equals sign, \w+ consumes the remaining suffix, = fails, and the unanchored engine restarts at the next character. The default inline tokenizer extracts this attacker string directly from a syntactically complete [shortcode attributes] token.

import { createInlineMarkdownSpec } from &#039;@tiptap/core&#039;
const tokenizer = createInlineMarkdownSpec({ nodeName: &#039;probe&#039;, selfClosing: true }).markdownTokenizer
const source = `[probe ${&#039;0&#039;.repeat(32768)}]`
const started = performance.now()
tokenizer.tokenize(source, [], {})
console.log(performance.now() - started)

At 1,032, 2,056, 4,104, 8,200, 16,392, and 32,776 bytes, candidates took 3.24, 12.88, 54.82, 136.91, 557.83, and 2,209.47 ms. Equal-length hyphen controls took 0.02 to 0.19 ms.

Impact

Applications parsing attacker-controlled Markdown with these helpers can have a browser main thread, server event loop, or worker blocked by a small input. Persisted documents can repeatedly freeze clients; repeated requests can exhaust server-side parsing capacity. Editors that only consume validated ProseMirror JSON and never invoke the Markdown parsing path are not directly affected through document content.

History and remediation

Commit 35645d94ae9cd73448a564104c2e08f64e9564bc introduced both parsers on 14 October 2025, first released in 3.7.0. Versions 3.7.0 through current 3.29.2 and current main remain affected. Official issue, PR, and repository-advisory searches found no duplicate.

Require a start-of-string or whitespace boundary before both key-value parsers, and preferably replace the multi-pass placeholder and shortcode regex designs with deterministic single-pass tokenizers. Keep quoted values out-of-band so attacker input cannot collide with predictable __QUOTED_n__ placeholders. Add complete block and inline Markdown-tokenizer scaling regressions with equal-length controls.

Please credit GitHub user joostgrunwald as finder/reporter.

Published: Sep 8, 2026
Updated: Sep 9, 2026
GHSA: GHSA-j95f-988m-3j2f
Severity: High
Exploit:
CISA KEV:

No technical information available.

CWEs:

Affected Software
References

Software	Affected versions
@tiptap / core	`>= 3.7.0, < 3.30.5`

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Frequently Asked Questions

What is a Vulnerability (CVE) and why does it matter?

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.

Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.

Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.