CVE catalog
CVE-2026-88753
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) v
- Severity
- High · CVSS 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Published
- Updated
- Source
- [NVD] · [CVE record]
- EPSS
- 0.39% · Oct 25, 2026
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.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | python-markdown2 | sid | 2.5.4-4 | vulnerable |
| Debian | python-markdown2 | forky | 2.5.4-4 | vulnerable |
| Debian | python-markdown2 | trixie | 2.4.11-1 | vulnerable |
| Debian | python-markdown2 | bookworm | 2.4.1-1 | vulnerable |
| Ubuntu | python-markdown2 | 20.04 | 2.3.7-2 | vulnerable |
| Ubuntu | python-markdown2 | 22.04 | 2.3.10-1.1 | vulnerable |
| Ubuntu | python-markdown2 | 22.04 | 2.4.1-1 | vulnerable |
| Ubuntu | python-markdown2 | 24.04 | 2.4.1-1 | vulnerable |
| Ubuntu | python-markdown2 | 24.04 | 2.4.11-1 | vulnerable |
| Ubuntu | python-markdown2 | 26.10 | 2.5.4-3 | vulnerable |
| Ubuntu | python-markdown2 | 26.04 | 2.4.11-1 | vulnerable |
| Ubuntu | python-markdown2 | 26.04 | 2.5.4-2 | vulnerable |
| Ubuntu | python-markdown2 | 26.04 | 2.5.4-3 | vulnerable |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | python-markdown2 | source | sid | (unfixed) | not yet assigned | Not reported | [1151085] |
| Debian | python-markdown2 | source | forky | (unfixed) | not yet assigned | Not reported | [1151085] |
| Debian | python-markdown2 | source | trixie | (unfixed) | not yet assigned | Not reported | [1151085] |
| Debian | python-markdown2 | source | bookworm | (unfixed) | not yet assigned | Not reported | [1151085] |
Notes
[trixie] python-markdown2: Minor issue
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [python3-markdown2]Affected
Source package: [python-markdown2]
Details (2)
2.4.1-1· all · bookwormAffected
nvd · python-markdown2 · debian · bookworm; nvd · python-markdown2 · debian · 12
2.4.1-1· all · bookwormAffected
nvd · python-markdown2 · debian · bookworm; nvd · python-markdown2 · debian · 12
[Debian 13 (Trixie)]
- [python3-markdown2]Affected
Source package: [python-markdown2]
Details (2)
2.4.11-1· all · trixieAffected
nvd · python-markdown2 · debian · 13
2.4.11-1· all · trixieAffected
nvd · python-markdown2 · debian · 13
Observed:
References
- [https://ftp.suse.com/pub/projects/security/csaf/opensuse-su-2026_12159-1.json]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-88753]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-88753]
- [https://osv.dev/vulnerability/UBUNTU-CVE-2026-88753]
- [https://security-tracker.debian.org/tracker/CVE-2026-88753]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-88753.json]
[Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]