CVE Intelligence
High File handling

CVE-2026-115353 — Mistune before 3.3.0 Path Traversal via include Directive

Mistune before 3.3.0 contains a path traversal vulnerability in the RST include directive that allows attackers to read arbitrary files by supplying relative or absolute paths. Attackers can submit markdown containing include directives referencing ../ sequences or absolute paths to embed sensitive files like credentials or environment data in rendered HTML.

Published Oct 22, 2026 · Updated Oct 22, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: VulnCheck

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.4% (30-day exploitation probability)+5
  • Technical severity (high)+6

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.39%
ahead of 33% of scored CVEs · Oct 27, 2026
Affects
Lepture
Mistune
CVSS base
8.6
High · 2 source(s)

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Lepture Mistune).
  2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  3. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  4. Search available logs for exploit probes matching the vulnerability class (file handling), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Lepture Mistune < 3.3.0 Vulnerable CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
None
Availability
None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
9.2 CVSS 4.0 Critical — — disclosure@vulncheck.com via NIST National Vulnerability Database
9.2 CVSS 4.0 Critical — — VulnCheck via CVE Program (cve.org) e CISA ADP
8.6 CVSS 3.1 High 3.9 4.0 disclosure@vulncheck.com via NIST National Vulnerability Database
8.6 CVSS 3.1 High — — VulnCheck via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N (score shown at the top: disclosure@vulncheck.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-22 · Path Traversal

Other CVEs with this weakness →

EPSS over time FIRST

Oct 23, 2026 → Oct 27, 2026 · 5 reading(s) · max 0.39%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
  • Monitor file creation in web directories and paths with traversal sequences (../).
web/proxy/WAF logsnetwork IDS/IPSfile integrity (FIM)endpoint telemetry (EDR)

Timeline

What happened to this CVE, newest first.

  • 2026
  • Affected products added · lepture/mistune
    Oct 22, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 22, 2026
  • CVSS changed · 8.6
    Oct 22, 2026 · NIST National Vulnerability Database
  • Source status changed · → Deferred
    Oct 22, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 22, 2026 · Alertas do Telegram
  • CVE published
    Oct 22, 2026 · VulnCheck

Source activity

Repeated readings are counted rather than listed.

  • 1× References added · Oct 22, 2026 – Oct 22, 2026
  • 1× Official description updated · Oct 22, 2026 – Oct 22, 2026

References

2 on the record

Elsewhere on this site

Lepture
every CVE for this vendor
File handling
same class
CWE-22
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-115355 Mistune before 3.3.0 Path Traversal and XSS via Include Directive 6d
  • CVE-2026-115352 Mistune before 3.3.0 Quadratic-Time DoS via Unmatched Brackets in Inline Parser 6d
  • CVE-2026-115354 Mistune before 3.3.0 Arbitrary Local File Read via Include Directive 6d
  • CVE-2026-115347 Mistune before 3.3.0 Quadratic Denial of Service via parse_link_text 6d
  • CVE-2026-115348 Mistune before 3.3.0 Quadratic-Time DoS via parse_link_text 6d
  • CVE-2026-115349 Mistune 3.0.0 before 3.3.0 Denial of Service via Nested Bracket Parsing 6d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No fixed version, patch or mitigation documented.
  • No CISA SSVC assessment.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-115353 is "Mistune before 3.3.0 Path Traversal via include Directive", rated High. It affects Mistune (Lepture); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 8.6 describes technical severity. EPSS 0.39% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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