CVE-2026-86435
commonmark versions from 1.5.0 before 2.8.4 contain a denial of service vulnerability in the Footnote extension that fails to deduplicate footnote definitions. Attackers can craft documents with duplicate footnote definitions and references to create quadratic output expansion, consuming excessive memory and CPU to exhaust server resources.
Scoring
- Severity
- HIGH
- CVSS base score
- 8.7
- CVSS vector
- CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- EPSS probability
- 0.28%
- CWE
- CWE-407
- Published
- 2026-09-07
- Last modified
- 2026-09-09
Affected products
- thephpleague commonmark
- thephpleague commonmark
Weakness type
Related vulnerabilities
- CVE-2026-87822 — t-digest 3.1 through 3.3 Denial of Service via NaN Centroid Means in MergingDigest.fromBytes
- CVE-2024-58382 — league/commonmark before 2.6.0 Denial of Service via Quadratic Complexity
- CVE-2023-54395 — PocketMine-MP before 4.12.5 Denial of Service via ModalFormResponsePacket
- CVE-2026-86434 — commonmark 2.0.0 through 2.8.3 Denial of Service via Slug Collision
- CVE-2026-86433 — commonmark 1.5.0 before 2.8.4 Denial of Service via Attributes
- CVE-2026-86430 — league/commonmark before 2.9.1 Denial of Service via parsing
- CVE-2026-86429 — commonmark before 2.9.1 Denial of Service via SmartPunct and Attributes
- CVE-2026-86428 — commonmark 1.5.0 before 2.10.0 Denial of Service via Attributes