CVE-2023-26303 json
markdown-it-py crash on null assertions
published 2023-02-22 3 y ago modified 2026-06-17 4 mo ago also GHSA-vrjv-mxr7-vjf8 , PYSEC-2023-24 , EUVD-2023-0131
- cvss
- 3.3
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 13%
- public exploits
- 0
- none known
Summary
Denial of service could be caused to markdown-it-py, before v2.2.0, if an attacker was allowed to force null assertions with specially crafted input.
Patch / fix
- pypi markdown-it-py 2.2.0
- Executable Books markdown-it-py commit ae03c61, v2.2.0
- markdown-it-py Debian 14, Debian 13, Debian 12 2.1.0-5
debian advisories DEBIAN-CVE-2023-26303
- python-markdown-it-py openSUSE Tumbleweed 4.2.0-1.2
- python-markdown-it-py openSUSE Tumbleweed 2.2.0-1.1
opensuse advisories openSUSE-SU-2026:12015-1openSUSE-SU-2024:12772-1
Vendor advisories
What the vendors themselves say about their products: affected, fixed or not affected, and what to do.
red hat product security vex CVE-2023-26303 updated cvss 5.5
markdown-it-py: Denial of service by forcing null assertions with specially crafted input
-
Red Hat Ansible Automation Platform 2 ansible-lint, ansible-navigator, python-ansible-compat, python3x-ansible-compataffected: no fix available
Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 19 mo ago
Exploit prediction
0.22% chance of exploitation in the next 30 days, higher than 13% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 3.3 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L |
| NVD | 3.1 | 5.5 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
| GitHub | 3.1 | 5.5 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| pypi | markdown-it-py | <2.2.0 |
2.2.0 |
Affected products
- Executable Books markdown-it-py
Classification
- Weakness
-
- CWE-173 Improper Handling of Alternate Encoding
References
-
github.com
/executablebooks/markdown-it-py/commit/ae03c6107dfa18e648f6fdd1280f5b89092d5d49
patch, web
-
github.com
/executablebooks/markdown-it-py/pull/246
web
-
github.com
/executablebooks/markdown-it-py/commit/53ca3e9c2b9e9b295f6abf7f4ad2730a9b70f68c
web
-
nvd.nist.gov
/vuln/detail/CVE-2023-26303
advisory
-
github.com
/executablebooks/markdown-it-py
package
-
github.com
/pypa/advisory-database/tree/main/vulns/markdown-it-py/PYSEC-2023-24.yaml
web
-
github.com
/advisories/GHSA-vrjv-mxr7-vjf8
advisory
Sources
- CVE List CVE-2023-26303
- GitHub Advisory GHSA-vrjv-mxr7-vjf8
- NVD CVE-2023-26303
- OSV PYSEC-2023-24
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.