CVE-2026-88753

A Regular-Expression Denial of Service (ReDoS) in the Markdown2. extract_metadata() function (lib...

7.5 HighFix available

A Regular-Expression Denial of Service (ReDoS) in the Markdown2. extract_metadata() function (lib/markdown2.py) of trentm markdown2 through v2.5.5 allows attackers to cause a Denial of Service (DoS) via a crafted Markdown document.

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: None
Integrity: None
Availability: High

Exploit likelihood

0.39%Up 0.2 points since Oct 16, 2026

What each source reports

CVE List Score used 7.5

Record: CVE-2026-88753
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness: CWE-400
Updated: 2026-11-02

EUVDEUVD-2026-102186 7.5

Record: EUVD-2026-102186
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

GitHub AdvisoriesGHSA-vv85-hg53-g6g2 7.5

A Regular-Expression Denial of Service (ReDoS) in the Markdown2. extract_metadata() function (lib...

Record: GHSA-vv85-hg53-g6g2
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness: CWE-400
Updated: 2026-11-02

NVD 7.5

Record: CVE-2026-88753
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness: CWE-400
Updated: 2026-11-02

OSVDEBIAN-CVE-2026-88753 7.5

Record: DEBIAN-CVE-2026-88753
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

OSVUBUNTU-CVE-2026-88753 7.5

Record: UBUNTU-CVE-2026-88753
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

OSVopenSUSE-SU-2026:12159-1 No score

python313-markdown2-2.5.5-2.1 on GA media

These are all security issues fixed in the python313-markdown2-2.5.5-2.1 package on the GA media of openSUSE Tumbleweed.

Record: openSUSE-SU-2026:12159-1
Updated: 2026-11-02

Affected packages

Affected packages
Package	Affected	Fixed
`python-markdown2` Debian:12	All versions, plus listed versions 2.4.1-12.4.11-12.5.3-1~exp12.5.4-12.5.4-22.5.4-32.5.4-4	None known
`python-markdown2` Debian:13	All versions, plus listed versions 2.4.11-12.5.3-1~exp12.5.4-12.5.4-22.5.4-32.5.4-4	None known
`python-markdown2` Debian:14	All versions, plus listed versions 2.4.11-12.5.3-1~exp12.5.4-12.5.4-22.5.4-32.5.4-4	None known
`python-markdown2` Ubuntu:20.04:LTS	All versions, plus listed versions 2.3.7-2	None known
`python-markdown2` Ubuntu:22.04:LTS	All versions, plus listed versions 2.3.10-1.12.4.1-1	None known
`python-markdown2` Ubuntu:24.04:LTS	All versions, plus listed versions 2.4.1-12.4.11-1	None known
`python-markdown2` Ubuntu:26.10	All versions, plus listed versions 2.5.4-3	None known
`python-markdown2` Ubuntu:26.04:LTS	All versions, plus listed versions 2.4.11-12.5.4-22.5.4-3	None known
`python-markdown2` openSUSE:Tumbleweed	before 2.5.5-2.1	2.5.5-2.1

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-2026-88753 is a high vulnerability (CVSS 7.5) in python-markdown2, published October 15, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.39%, the 33rd percentile. Fixed in python-markdown2 2.5.5-2.1.