CVE-2023-26303 — Denial of service could be caused to markdown-it-py, before v2

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.

01What is this vulnerability?

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.

02Affected products

Vendor	Product	Versions
Executable Books	markdown	it-py — 0

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2023-02-22T23:44:40.711Z
• Last modified: 2025-03-11T18:22:36.539Z

09References

• github.com — https://github.com/executablebooks/markdown-it-py/commit/ae03c6107dfa18e648f6fdd…