GHSA-52mm-h59v-f3c7
GHSA-52mm-h59v-f3c7 is a CWE-83 vulnerability in earmark. O3 Security confirms whether GHSA-52mm-h59v-f3c7 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
earmark: Stored XSS via unescaped HTML attribute values
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-52mm-h59v-f3c7.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
earmarkReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Hex packages — download data is not available via public APIs for these ecosystems.
Description
Improper Neutralization of Script in Attributes in a Web Page vulnerability in pragdave earmark allows stored cross-site scripting via unescaped HTML attribute values.
'Elixir.Earmark.Transform':_make_att1/2 in lib/earmark/transform.ex splices attribute values verbatim between two literal " bytes: [" ", name, "="", value, """]. Text nodes are routed through the existing escape function which encodes " as ", but attribute values never visit that path. A markdown link whose URL or title contains a bare " closes the attribute early and lets the trailing bytes be parsed by the browser as fresh HTML attributes. For example, [click](http://example.com/?a=x" onerror="alert(1)) renders as <a href="http://example.com/?a=x" onerror="alert(1)">click</a>, executing arbitrary JavaScript in the victim's browser.
The earmark library is no longer maintained and has been retired on Hex. No patched version will be released. All releases from 1.4.1 onward are affected, and users should migrate to a maintained Markdown library such as MDEx.
This issue affects earmark from 1.4.1 onward.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💧Hex | earmark | ≥ 1.4.1 | No fix |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for earmark. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Remediation status
No patched version of earmark has shipped for GHSA-52mm-h59v-f3c7 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-52mm-h59v-f3c7 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-52mm-h59v-f3c7. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-52mm-h59v-f3c7 in your dependencies?
O3 detects GHSA-52mm-h59v-f3c7 across Hex dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.