Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
lepture mistune — Mistune plugins/formatting: quadratic-time parsing on long runs of `~~x~~`, `==x==`, and `^^x^^` markers (strikethrough / mark / insert)
AV AC PR UI S C I A CVSS EPSS %ile KEV
N L N N U N N H 7.5 .0042 35.0 —
AFFECTED
Product Versions Fixed
mistune < 3.3.0 – —
TIMELINE
Jul 7 Reserved by GitHub_M
Jul 8 EXPLOIT PUBLISHED — CVE-2026-59922 (lepture mistune). Public exploit reference added.
Jul 8 Published (CNA: GitHub_M)
Description
Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, a run of closed tilde, equals-sign, or caret marker pairs around a character causes quadratic work in src/mistune/plugins/formatting.py when the strikethrough, mark, or insert plugin scans for matching markers from each possible start position, allowing denial of service through CPU exhaustion. This issue is fixed in version 3.3.0.
Lifecycle
Complete event history — 3 events, chronological
| Date | Event | Detail |
|---|
| July 7, 2026 | Reserved | Reserved by GitHub_M |
| July 8, 2026 | EXPLOIT PUBLISHED | EXPLOIT PUBLISHED — CVE-2026-59922 (lepture mistune). Public exploit reference added. |
| July 8, 2026 | Published | Published (CNA: GitHub_M) |
Affected
Affected products and packages — 1 row
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
|---|
| lepture | mistune | — | < 3.3.0 | — |
About this page
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-59922 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.