- Reported
-
- Issued
-
- Package
-
pulldown-cmark
(crates.io)
- Type
-
Vulnerability
- Categories
-
- Keywords
-
#markdown
#wikilinks
#memory-exhaustion
- References
-
- CVSS Score
- 7.5
HIGH
- CVSS Details
-
- Attack Vector
- Network
- Attack Complexity
- Low
- Privileges Required
- None
- User Interaction
- None
- Scope
- Unchanged
- Confidentiality Impact
- None
- Integrity Impact
- None
- Availability Impact
- High
- CVSS Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Patched
-
- Unaffected
-
Description
When Options::ENABLE_WIKILINKS is enabled, a wikilink with a pipe separator
and empty display text, such as [[a|]], leaks its child node's sibling chain
into the content that follows it. Each such link roughly doubles the number of
events the parser yields for the rest of the document, so output grows
exponentially with input size: 16 repetitions of [[a|]] (112 bytes) yield
327,676 events, where the fixed parser yields 65. A document of a few kilobytes
is enough to exhaust memory in a process that collects the events or renders
them to HTML.
Applications that parse untrusted Markdown with ENABLE_WIKILINKS set,
including through Options::all(), are affected. The option is off by default.
Parsing without it is not affected.
The flaw was fixed in
#1102 and
released in 0.13.5.
Advisory available under CC0-1.0
license.