python-markdown2 through 2.5.5 contains a denial of service vulnerability that allows remote users to exhaust CPU by submitting Markdown…
CVE-2026-118694
python-markdown2 through 2.5.5 contains a denial of service vulnerability that allows remote users to exhaust CPU by submitting Markdown with unclosed inline link destinations. Attackers can submit repeated '[a](' or '
- Severity
- High
- Known exploited
- Not listed in CISA KEV
- Exploit availability
- Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
- Published
- 28 October 2026
- Last updated
- 29 October 2026
- Weakness
- CWE-407
- Assigner
- disclosure@vulncheck.com
CVSS vectorCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/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
At the source
References
- https://github.com/trentm/python-markdown2
- https://github.com/trentm/python-markdown2/blob/2.5.5/lib/markdown2.py#L1478-L1492
- https://github.com/trentm/python-markdown2/blob/2.5.5/lib/markdown2.py#L3029
- https://github.com/trentm/python-markdown2/issues/750
- https://github.com/trentm/python-markdown2/pull/751
- https://www.vulncheck.com/advisories/python-markdown2-through-2.5.5-denial-of-service-via-unclosed-inline-link-destinations
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