# CVE-2026-58486 — hedgedoc

> As of 2026-07-14, CVE-2026-58486 is a High-severity (band derived from the CVSS v4.0 score, not stated by the CNA) vulnerability in hedgedoc, CVSS v4.0 8.3, EPSS 0.2% (14.3th percentile). No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-58486 as of 2026-07-14; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

**Last updated:** 2026-07-14

## What is CVE-2026-58486?

HedgeDoc is an open source, real-time, collaborative, markdown notes application. Prior to version 1.11.0, HedgeDoc was vulnerable to a YAML alias bomb due to unsafe processing of the note frontmatter. HedgeDoc parsed frontmatter with js-yaml.load (js-yaml v3) via @hedgedoc/meta-marked, which resolved YAML anchor aliases. A compact malicious payload could therefore expand into a huge object structure, consuming excessive CPU. This expansion ran on every request to the publish view (/s/) and, when placed under the opengraph key, the editor view (/). A ten-level alias bomb could block the single Node.js event loop for roughly 235 seconds per request, causing concurrent requests to hang or drop and rendering the instance unavailable (DoS). Because the note was stored in the database, the impact survived process restarts until the note was removed. toobusy-js did not reliably mitigate the worst cases, as the event loop was saturated before the middleware could respond. This issue was fixed in version 1.11.0.

The record classifies CVE-2026-58486 under weakness classes [CWE-400](https://intel.threadlinqs.com/cwe/CWE-400), [CWE-409](https://cwe.mitre.org/data/definitions/409.html). 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 84 days ago.

## Severity and exploitation probability

- **CVSS v4.0 base score:** 8.3 — High (derived from score) (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H`)
- **EPSS (FIRST):** 0.2% probability of exploitation in the next 30 days, higher than 14.3% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 4.7/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-07-13, last modified 2026-07-14

## Is CVE-2026-58486 being exploited?

It currently carries a trending score of 33 in the Threadlinqs vulnerability feed.

## Affected products and versions

- **hedgedoc**: hedgedoc

## How to fix CVE-2026-58486

No vendor patch reference has been recorded for CVE-2026-58486 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-58486

No threat campaign in the Threadlinqs corpus currently references CVE-2026-58486, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.

## Sources

Enriched from CVE.org, NVD, FIRST EPSS. Last verified by Threadlinqs on 2026-07-15. This product uses the NVD API but is not endorsed or certified by the NVD.

**Vendor advisory and patch**

- [github.com](https://github.com/hedgedoc/hedgedoc/security/advisories/GHSA-qj78-mjch-wwrv)

**Other references**

- [github.com](https://github.com/hedgedoc/hedgedoc/commit/c489497e451887bfe400434c5a010940051e9890)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-58486
Full detection coverage and IOCs for threats exploiting CVE-2026-58486 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp