{"items":[{"id":"NVI-00018505","kind":"vulnerability","title":"Mistune TOC Anchor Injection XSS","revision":1,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-6269-cqxg-mhhv","CVE-2026-44898"],"plain_summary":"GitHub lists this reviewed advisory for mistune. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.","review_status":"source_listed","control_topics":[],"public_actions":[{"summary":"Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.","source_ids":["sr-32b6f3c7f5600c3a785df7274bb8d7e8"],"action_type":"investigate","limitations":"Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system.","current_supported_target":null}],"schema_version":"1.1.0","source_metrics":[{"kind":"CVSS","as_of":"2026-06-08T23:30:27.000Z","value":"6.1 medium","meaning":"GitHub source severity; exploitability and local consequence require separate evidence.","source_id":"sr-32b6f3c7f5600c3a785df7274bb8d7e8"}],"why_it_matters":"Published affected context helps an owner decide what evidence to gather. This report has not examined your application.","related_sources":[{"id":"sr-32b6f3c7f5600c3a785df7274bb8d7e8","url":"https://github.com/advisories/GHSA-6269-cqxg-mhhv","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-6269-cqxg-mhhv","publisher":"GitHub Advisory Database","observed_at":"2026-11-07T00:50:36.189Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-32b6f3c7f5600c3a785df7274bb8d7e8"],"technology":"mistune","known_exclusions":[],"conditions_summary":"## Summary\n`render_toc_ul()` builds a `` table-of-contents tree from a list of `(level, id, text)` tuples. Both the `id` value (used as `href=\"#\"`) and the `text` value (used as the visible link label) are inserted into `` tags via a plain Python format string — with no HTML escaping applied to either value.\n\nWhen heading IDs are derived from user-supplied heading text (the standard use-case for readable slug anchors), an attacker can craft a heading whose text breaks out of the `href=\"#...\"` attribute context, injecting arbitrary HTML tags including `` blocks directly into the rendered TOC.\n\nThis vulnerability is closely related to H2 (unescaped `id=` in `heading()`): the same `heading_id` callback pattern that triggers H2 also populates the `toc_items` list that `render_toc_ul()` consumes, meaning both vulnerabilities fire simultaneously in a typical documentation setup.\n\n## Details\n**File:** `src/mistune/toc.py`\n\n```python\ndef render_toc_ul(toc):\n    ...\n    for level, k, text in toc:\n        # k   = heading id  (used verbatim as href fragment)\n        # text = heading text (used verbatim as link label)\n        item = '{}'.format(k, text)\n   ","public_affected_ranges":["= 3.2.0"]}],"null_published_at":"2026-11-07T07:07:39.844Z","source_updated_at":"2026-06-08T23:30:27.000Z","source_disclosed_at":"2026-05-14T16:36:12.000Z","is_synthetic_fixture":false,"null_last_reviewed_at":null,"public_change_summary":"First indexed by Null; source disclosure date is shown separately.","null_first_observed_at":"2026-11-07T00:50:36.189Z"}],"next_cursor":null,"snapshot_revision":"42594"}