What is CVE-2026-115348?

CVE-2026-115348 is a high-severity vulnerability in Lepture Mistune, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2026-10-22.

How severe is CVE-2026-115348?

High severity. CVSS v3 base score is 7.5 out of 10.

Resource exhaustion in Lepture Mistune

CVE-2026-115348

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.

Vulnerability class: DoS (Denial of Service)

Published 2026-10-22 · last modified 2026-10-22.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Lepture Mistune

Weakness classification (CWE)

CWE-400 — Uncontrolled Resource Consumption

References

github.com/lepture/mistune/security/advisories/GHSA-x2gr-6qf2-fc9x (vendor-advisory)
www.vulncheck.com/advisories/mistune-before-3.3.0-quadratic-time-dos-via-parse-… (third-party-advisory)

Frequently asked questions

What is CVE-2026-115348?: CVE-2026-115348 is a high-severity vulnerability in Lepture Mistune, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2026-10-22.
How severe is CVE-2026-115348?: High severity. CVSS v3 base score is 7.5 out of 10.