CVE-2026-33079
Mistune has a ReDoS in LINK_TITLE_RE that allows denial of service via crafted Markdown input
描述
In versions 3.0.0a1 through 3.2.0 of Mistune, there is a ReDoS (Regular Expression Denial of Service) vulnerability in `LINK_TITLE_RE` that allows an attacker who can supply Markdown for parsing to cause denial of service. The regular expression used for parsing link titles contains overlapping alternatives that can trigger catastrophic backtracking. In both the double-quoted and single-quoted branches, a backslash followed by punctuation can be matched either as an escaped punctuation sequence or as two ordinary characters, creating an ambiguous pattern inside a repeated group. If an attacker supplies Markdown containing repeated ! sequences with no closing quote, the regex engine explores an exponential number of backtracking paths. This is reachable through normal Markdown parsing of inline links and block link reference definitions. A small crafted input can therefore cause significant CPU consumption and make applications using Mistune unresponsive.
如何修補 CVE-2026-33079
要修補 CVE-2026-33079,請將受影響套件升級到下列已修補版本。
- —升級至 3.2.1 或更新版本
- —升級至 3.2.1 或更新版本
CVE-2026-33079 正在被利用嗎?
低 — EPSS 為 0.5%,目前沒有觀察到大規模利用活動。
受影響套件(2)
- >= 3.0.0a1, < 3.2.1
- >= 3.0.0a1, < 3.2.1
CVSS 分數
| 來源 | 版本 | 嚴重程度 | 向量 |
|---|---|---|---|
| osv | CVSS 4.0 | — | 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 |