{"items":[{"id":"NVI-00005098","kind":"vulnerability","title":"league/commonmark: Denial of service via deeply nested XML output","revision":1,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-mj63-m3rc-8ppr"],"plain_summary":"OSV carries this publisher advisory for league/commonmark. This is an aggregated source copy; consult the original publisher and compare update dates.","review_status":"source_listed","control_topics":[],"public_actions":[{"summary":"The original advisory lists fixed boundaries 2.9.0 for league/commonmark. Confirm the publisher’s latest guidance.","source_ids":["sr-81ba4ff95fc229005c34dd6d8adb85c8"],"action_type":"vendor_patch","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":[],"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-81ba4ff95fc229005c34dd6d8adb85c8","url":"https://github.com/advisories/GHSA-mj63-m3rc-8ppr","basis":"vendor_advisory","notes":"GitHub-origin advisory, CC-BY-4.0; OSV is an aggregate copy, not independent corroboration.","title":"GHSA-mj63-m3rc-8ppr","publisher":"GitHub Advisory Database via OSV","observed_at":"2026-10-31T21:42:30.980Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-81ba4ff95fc229005c34dd6d8adb85c8"],"technology":"league/commonmark","known_exclusions":[],"conditions_summary":"### Impact\n\n`XmlRenderer` pretty-prints XML by emitting depth-proportional indentation whitespace for **every** opening and closing tag. For a tree of depth n, the indentation alone sums to **O(n²)** bytes of output (and corresponding memory), reachable through `MarkdownToXmlConverter` — e.g. `str_repeat('> ', $depth) . \"x\\n\"`, a single line of nested blockquotes — or through a direct `XmlRenderer::renderDocument()` call on an attacker-influenced AST.\n\nThis affects applications that convert untrusted Markdown to XML, which is an **opt-in** output path. The parser's `max_nesting_level` bounds the depth of *parser-created* trees, but its default is high enough to reach damaging sizes, can be raised by the host application, and does not constrain custom or programmatically built ASTs handed straight to the renderer. The result is a memory / output-size amplification rather than a hard crash, which is why this issue is rated **Medium** rather than High. No confidentiality or integrity impact. XML rendering was introduced in 2.0.0 (first shipped in 2.0.0-beta1, June 2021) and has emitted depth-proportional indentation ever since, so all 2.x releases are affected (verified against 2.8.x,","public_affected_ranges":["ECOSYSTEM: introduced 2.0.0; fixed 2.9.0"]}],"null_published_at":"2026-10-31T22:13:01.441Z","source_updated_at":"2026-08-06T20:45:15.556Z","source_disclosed_at":"2026-08-06T20:42:54.000Z","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":"2026-10-31T21:42:30.980Z"}],"next_cursor":null,"snapshot_revision":"42594"}