# RUSTSEC-2026-0414: Exponential event growth with `ENABLE_WIKILINKS`


- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 18 Oct 2026

## What is RUSTSEC-2026-0414?

RUSTSEC-2026-0414 is a vulnerability in pulldown-cmark, published on 18 Oct 2026. 

### Official 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](https://github.com/pulldown-cmark/pulldown-cmark/pull/1102) and
released in 0.13.5.

## Which versions are affected by RUSTSEC-2026-0414?

1 open source package ship an affected version, including pulldown-cmark.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `pulldown-cmark` | crates.io | From 0.13.0 | 0.13.5 |

## How do I fix RUSTSEC-2026-0414?

Upgrade pulldown-cmark to 0.13.5 or later.

## Is RUSTSEC-2026-0414 being exploited?

There is no known exploitation of RUSTSEC-2026-0414 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for RUSTSEC-2026-0414 and fix it if it is affected.

What it is: RUSTSEC-2026-0414 is a vulnerability in pulldown-cmark, published on 18 Oct 2026. 
Exploitation: There is no known exploitation of RUSTSEC-2026-0414 in the wild and no public exploit code.

Affected packages and fixed versions:
- pulldown-cmark (crates.io): affected from 0.13.0; fixed in 0.13.5

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/RUSTSEC-2026-0414/ (Markdown: https://insights.sbomify.com/RUSTSEC-2026-0414/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/RUSTSEC-2026-0414

---
From sbomify Insights: https://insights.sbomify.com/RUSTSEC-2026-0414/
Summaries are generated and may contain mistakes; the official description above is the record.