High 7.5Published Oct 22, 2026

CVE-2026-115348Mistune before 3.3.0 Quadratic-Time DoS via parse_link_text

Updated under an hour ago (Oct 27, 2026, 5:30 AM ET)

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It affects lepture mistune. Add what you run to find out whether that includes you.

EPSS puts the chance of exploitation in the next 30 days at 0.44%, higher than 38% of scored CVEs.

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Every CVE for lepture mistune

Exploited in the last 30 days

Mistune from 3.0.0 before 3.3.0 contains an algorithmic complexity vulnerability in the inline link parser's parse_link_text function that allows unauthenticated attackers to exhaust CPU with unbalanced brackets. Attackers can submit Markdown containing many unbalanced '[' or '![' characters, forcing repeated unbounded forward scans and tying up worker processes for minutes.

CVSS: 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-400
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): 0.44% (percentile 38)
Assigned by: VulnCheck
NVD analysis: Deferred
Record last updated: Oct 23, 2026
First seen by InfoSec Signals: Oct 22, 2026

Affected products

Affected products

lepture mistune lepture:mistune (from the name)	from 3.0.0 before 3.3.0; 3.3.0 not affected	CNA record

References

References

https://github.com/lepture/mistune/security/advisories/GHSA-x2gr-6qf2-fc9x	vendor-advisory
https://www.vulncheck.com/advisories/mistune-before-3.3.0-quadratic-time-dos-via-parse-link-text	third-party-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.