CVE-2026-115354

Mistune before 3.3.0 Arbitrary Local File Read via Include Directive

7.1 High

Mistune before 3.3.0 contains a path traversal vulnerability in the opt-in Include directive that allows attackers to read local files by supplying relative or absolute include paths. Attackers who submit Markdown rendered via Markdown.read() can disclose files such as /etc/passwd and inject unescaped HTML or script content into rendered output.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: Passive

What an attacker can affect

Confidentiality: High
Integrity: None
Availability: None

Exploit likelihood

0.47%Up 0.1 points since Oct 23, 2026

What each source reports

CVE List Score used 7.1

Mistune before 3.3.0 Arbitrary Local File Read via Include Directive

Record: CVE-2026-115354
CVSS 4.0: 7.1 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
Weakness: CWE-22
Updated: 2026-11-02

EUVDEUVD-2026-108423 7.1

Record: EUVD-2026-108423
CVSS 4.0: 7.1 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
Updated: 2026-11-02

GitHub AdvisoriesGHSA-r6px-88r6-4rqg 7.1

Mistune before 3.3.0 contains a path traversal vulnerability in the opt-in Include directive that...

Record: GHSA-r6px-88r6-4rqg
CVSS 4.0: 7.1 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
Weakness: CWE-22
Updated: 2026-11-02

NVD 7.1

Record: CVE-2026-115354
CVSS 4.0: 7.1 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
Weakness: CWE-22
Updated: 2026-11-02

OSV 7.1

Mistune before 3.3.0 Arbitrary Local File Read via Include Directive

Record: CVE-2026-115354
CVSS 4.0: 7.1 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
Weakness: CWE-22
Updated: 2026-11-02

OSVDEBIAN-CVE-2026-115354 7.1

Record: DEBIAN-CVE-2026-115354
CVSS 4.0: 7.1 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Updated: 2026-11-02

OSVUBUNTU-CVE-2026-115354 7.1

Record: UBUNTU-CVE-2026-115354
CVSS 4.0: 7.1 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
Updated: 2026-11-02

Affected products

lepture mistune

Affected packages

Affected packages
Package	Affected	Fixed
`mistune` Debian:12	All versions, plus listed versions 2.0.4-12.0.4-23.0.2-13.0.2-23.1.3-13.1.4-13.3.4-13.4.0-1	None known
`mistune` Debian:13	All versions, plus listed versions 3.1.3-13.1.4-13.3.4-13.4.0-1	None known
`mistune` Debian:14	All versions, plus listed versions 3.1.3-13.1.4-13.3.4-13.4.0-1	None known
`mistune` Ubuntu:16.04:LTS	All versions, plus listed versions 0.6-20.7.1-1	None known
`mistune` Ubuntu:18.04:LTS	All versions, plus listed versions 0.7.4-10.8-10.8.1-10.8.3-2	None known
`mistune` Ubuntu:20.04:LTS	All versions, plus listed versions 0.8.4-10.8.4-2	None known
`mistune` Ubuntu:22.04:LTS	All versions, plus listed versions 0.8.4-40.8.4-52.0.0-1+really0.8.4-1	None known
`mistune` Ubuntu:24.04:LTS	All versions, plus listed versions 2.0.4-23.0.2-1	None known
`mistune` Ubuntu:26.10	All versions, plus listed versions 3.1.4-1	None known
`mistune` Ubuntu:26.04:LTS	All versions, plus listed versions 3.1.3-13.1.4-1	None known

History

History
Recorded	Changed	Sources
Nov 2, 2026	first indexed	CVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-115354 is a high vulnerability (CVSS 7.1) in Lepture Mistune, published October 22, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.47%, the 40th percentile. No source names a fixed version.