CVE detail
CVE-2026-33079
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.
Buzz score
Why this CVE is surfacing
This all-time snapshot uses the same composite formula as Trending across a 30-year evidence window, rather than a current rolling window.
Buzz score components · mention 20.8 · diversity 18.0 · KEV 0.0 · OTX 0.0 · PoC 0.0
Why it matters now
Mention timeline
- Total mentions
- 0
- within the 30d window
- Peak daily
- 0
- highest bucket
Evidence
Source links by recency
7 source links · newest first
- CVE-2026-33079 Mistune ReDoS in LINK_TITLE_RE allows denial of service with crafted Markdown titlesMicrosoft MSRC
Information published.
vendormsrc.microsoft.comMay 10, 2026, 8:03 AM - https://access.redhat.com/errata/RHSA-2026:43038access.redhat.com
No excerpt available.
Vendor Advisoryaccess.redhat.comMay 6, 2026, 6:16 PM - https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33079.jsonsecurity.access.redhat.com
No excerpt available.
Vendor Advisorysecurity.access.redhat.comMay 6, 2026, 6:16 PM - https://bugzilla.redhat.com/show_bug.cgi?id=2467298bugzilla.redhat.com
No excerpt available.
Exploitbugzilla.redhat.comMay 6, 2026, 6:16 PM - https://access.redhat.com/security/cve/CVE-2026-33079access.redhat.com
No excerpt available.
Vendor Advisoryaccess.redhat.comMay 6, 2026, 6:16 PM No excerpt available.
Exploitgithub.comMay 6, 2026, 6:16 PMNo excerpt available.
Exploitgithub.comMay 6, 2026, 6:16 PM
Exploit code
Public exploit repository references
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0 repository references · best confidence N/A · max 0 stars
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