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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used 9.2
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.
- Record
CVE-2026-115353- CVSS 4.0
- 9.2 Critical
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N - CVSS 3.1
- 8.6 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N - Weakness
- CWE-22
- Updated
- 2026-11-04
EUVDEUVD-2026-108422 9.2
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.
- Record
EUVD-2026-108422- CVSS 4.0
- 9.2 Critical
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N - Updated
- 2026-11-04
GitHub AdvisoriesGHSA-pfvv-4pq6-mx74 9.2
Mistune before 3.3.0 contains a path traversal vulnerability in the RST include directive that...
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.
- Record
GHSA-pfvv-4pq6-mx74- CVSS 4.0
- 9.2 Critical
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/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
- 8.6 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N - Weakness
- CWE-22
- Updated
- 2026-11-02
NVD 9.2
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.
- Record
CVE-2026-115353- CVSS 4.0
- 9.2 Critical
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/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
- 8.6 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N - Weakness
- CWE-22
- Updated
- 2026-11-04
OSV 9.2
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.
- Record
CVE-2026-115353- CVSS 4.0
- 9.2 Critical
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N - Weakness
- CWE-22
- Updated
- 2026-11-05
OSVDEBIAN-CVE-2026-115353 9.2
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.
- Record
DEBIAN-CVE-2026-115353- CVSS 4.0
- 9.2 Critical
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/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
- 2026-11-05
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OSVOESA-2026-4791 8.6
python-mistune security update
The python-mistune package is a fast yet powerful Python Markdown parser with renderers and plugins, compatible with sane CommonMark rules.
Security Fix(es):
Mistune before 3.3.0 contains a cross-site scripting vulnerability in the Include directive that emits included .html, .xhtml, or .htm file content as raw block_html tokens. Attackers who can plant an HTML file readable by the renderer can reference it via an include directive, combined with path traversal, to execute stored scripts when escape=False is set.(CVE-2026-115350)
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.(CVE-2026-115353)
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.(CVE-2026-115354)
Mistune before 3.3.0 contains a path traversal vulnerability in the Include directive that allows attackers to read arbitrary files by supplying ../ sequences in include paths. Attackers can also inject HTML through unescaped error messages and included file contents to perform cross-site scripting even when escape=True is set.(CVE-2026-115355)
- Record
OESA-2026-4791- CVSS 3.1
- 8.6 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N - Updated
- 2026-11-11
OSVOESA-2026-4793 8.6
python-mistune security update
The python-mistune package is a fast yet powerful Python Markdown parser with renderers and plugins, compatible with sane CommonMark rules.
Security Fix(es):
Mistune before 3.3.0 contains a cross-site scripting vulnerability in the Include directive that emits included .html, .xhtml, or .htm file content as raw block_html tokens. Attackers who can plant an HTML file readable by the renderer can reference it via an include directive, combined with path traversal, to execute stored scripts when escape=False is set.(CVE-2026-115350)
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.(CVE-2026-115353)
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.(CVE-2026-115354)
Mistune before 3.3.0 contains a path traversal vulnerability in the Include directive that allows attackers to read arbitrary files by supplying ../ sequences in include paths. Attackers can also inject HTML through unescaped error messages and included file contents to perform cross-site scripting even when escape=True is set.(CVE-2026-115355)
- Record
OESA-2026-4793- CVSS 3.1
- 8.6 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N - Updated
- 2026-11-11
OSVOESA-2026-4794 8.6
python-mistune security update
The python-mistune package is a fast yet powerful Python Markdown parser with renderers and plugins, compatible with sane CommonMark rules.
Security Fix(es):
Mistune before 3.3.0 contains a cross-site scripting vulnerability in the Include directive that emits included .html, .xhtml, or .htm file content as raw block_html tokens. Attackers who can plant an HTML file readable by the renderer can reference it via an include directive, combined with path traversal, to execute stored scripts when escape=False is set.(CVE-2026-115350)
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.(CVE-2026-115353)
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.(CVE-2026-115354)
Mistune before 3.3.0 contains a path traversal vulnerability in the Include directive that allows attackers to read arbitrary files by supplying ../ sequences in include paths. Attackers can also inject HTML through unescaped error messages and included file contents to perform cross-site scripting even when escape=True is set.(CVE-2026-115355)
- Record
OESA-2026-4794- CVSS 3.1
- 8.6 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N - Updated
- 2026-11-11
OSVUBUNTU-CVE-2026-115353 9.2
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.
- Record
UBUNTU-CVE-2026-115353- CVSS 4.0
- 9.2 Critical
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N - CVSS 3.1
- 8.6 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N - Updated
- 2026-11-02
OSVopenSUSE-SU-2026:12407-1No score
python313-mistune-3.4.0-2.1 on GA media
These are all security issues fixed in the python313-mistune-3.4.0-2.1 package on the GA media of openSUSE Tumbleweed.
- Record
openSUSE-SU-2026:12407-1- Updated
- 2026-11-04
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
mistuneDebian: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 |
mistuneDebian:13 | All versions, plus listed versions 3.1.3-13.1.4-13.3.4-13.4.0-1 | None known |
mistuneDebian:14 | All versions, plus listed versions 3.1.3-13.1.4-13.3.4-13.4.0-1 | None known |
python-mistuneopenEuler:24.03-LTS-SP4 From an advisory covering 4 CVEs | before 2.0.4-4.oe2403sp4 | 2.0.4-4.oe2403sp4 |
python-mistuneopenEuler:24.03-LTS-SP1 From an advisory covering 4 CVEs | before 2.0.4-4.oe2403sp1 | 2.0.4-4.oe2403sp1 |
python-mistuneopenEuler:24.03-LTS-SP3 From an advisory covering 4 CVEs | before 2.0.4-4.oe2403sp3 | 2.0.4-4.oe2403sp3 |
mistuneUbuntu:16.04:LTS | All versions, plus listed versions 0.6-20.7.1-1 | None known |
mistuneUbuntu:18.04:LTS | All versions, plus listed versions 0.7.4-10.8-10.8.1-10.8.3-2 | None known |
mistuneUbuntu:20.04:LTS | All versions, plus listed versions 0.8.4-10.8.4-2 | None known |
mistuneUbuntu:22.04:LTS | All versions, plus listed versions 0.8.4-40.8.4-52.0.0-1+really0.8.4-1 | None known |
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| Package | Affected | Fixed |
|---|---|---|
mistuneUbuntu:24.04:LTS | All versions, plus listed versions 2.0.4-23.0.2-1 | None known |
mistuneUbuntu:26.10 | All versions, plus listed versions 3.1.4-1 | None known |
mistuneUbuntu:26.04:LTS | All versions, plus listed versions 3.1.3-13.1.4-1 | None known |
python-mistuneopenSUSE:Tumbleweed From an advisory covering 4 CVEs | before 3.4.0-2.1 | 3.4.0-2.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, aliases, references | OSV | |
| affected, facts | EUVD, NVD, OSV | |
| references | CVE List | |
| affected, aliases, facts, references | OSV | |
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-115353 is a critical vulnerability (CVSS 9.2) 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 0.39%, the 33rd percentile. No source names a fixed version.
References
github.com/lepture/mistune/security/advisories/GHSA-9jjx-3hq3-hx4j
vulncheck.com/advisories/mistune-before-3.3.0-path-traversal-via-include-directive
nvd.nist.gov/vuln/detail/CVE-2026-115353
github.com/advisories/GHSA-pfvv-4pq6-mx74
github.com/CVEProject/cvelistV5/tree/main/cves/2026/115xxx/CVE-2026-115353.json
security-tracker.debian.org/tracker/CVE-2026-115353
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openeuler.org/zh/security/security-bulletins/detail?id=openEuler-SA-2026-4791
nvd.nist.gov/vuln/detail/CVE-2026-115350
nvd.nist.gov/vuln/detail/CVE-2026-115354
nvd.nist.gov/vuln/detail/CVE-2026-115355
openeuler.org/zh/security/security-bulletins/detail?id=openEuler-SA-2026-4793
openeuler.org/zh/security/security-bulletins/detail?id=openEuler-SA-2026-4794
ubuntu.com/security/CVE-2026-115353
cve.org/CVERecord?id=CVE-2026-115353
suse.com/security/cve/CVE-2026-115348
suse.com/security/cve/CVE-2026-115349
suse.com/security/cve/CVE-2026-115350
suse.com/security/cve/CVE-2026-115353