How severe is GHSA-3rcm-vjrc-p45j?

No CVSS score has been assigned to GHSA-3rcm-vjrc-p45j yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-3rcm-vjrc-p45j?

GHSA-3rcm-vjrc-p45j affects the following packages: justhtml (PyPI). Ecosystems affected: PyPI.

How do I fix GHSA-3rcm-vjrc-p45j?

Update justhtml to 1.12.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-3rcm-vjrc-p45j is resolved across your whole dependency graph.

How do I detect GHSA-3rcm-vjrc-p45j in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for justhtml, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-3rcm-vjrc-p45j if there is no patch (or I can't update yet)?

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 does O3 Security protect against GHSA-3rcm-vjrc-p45j?

O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-3rcm-vjrc-p45j can be triaged on real exposure rather than presence alone.

Is GHSA-3rcm-vjrc-p45j actively exploited in the wild?

No public exploit code has been indexed for GHSA-3rcm-vjrc-p45j yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-3rcm-vjrc-p45j?

GHSA-3rcm-vjrc-p45j has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 32th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-3rcm-vjrc-p45j?

GHSA-3rcm-vjrc-p45j is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was GHSA-3rcm-vjrc-p45j published, and has it been updated?

GHSA-3rcm-vjrc-p45j was published on March 18, 2026 and was last updated on August 24, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍 PyPI

Not in CISA KEV

GHSA-3rcm-vjrc-p45j — justhtml

GHSA-3rcm-vjrc-p45j is a Cross-site Scripting (XSS) vulnerability in justhtml. A fix is available for justhtml — see the affected versions and patch details below.

JustHTML has a Sanitizer Bypass (in Markdown)

Also known asCVE-2026-8445

Published

Mar 18, 2026

Updated

Aug 24, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Sep 23, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
A successful exploit gives an attacker total control of the affected component, not partial access.

Exploitation and automatability from CISA’s SSVC triage for GHSA-3rcm-vjrc-p45j.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs32th percentile — riskier than 32% of all scored CVEsHighest risk

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

1 pkg affected

🐍justhtml

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Summary

to_markdown() does not sufficiently escape text content that looks like HTML. As a result, untrusted input that is safe in to_html() can become raw HTML in Markdown output.

This is not specific to tokenizer raw-text states like <title>, <noscript>, or <plaintext>, although those states can trigger the behavior. The root cause is broader: Markdown text serialization leaves angle brackets unescaped in text nodes.

Details

When converting a parsed document to Markdown, text nodes are escaped for a small set of Markdown metacharacters, but HTML-significant characters such as < and > are preserved. That means content parsed as text, including entity-decoded text or text produced by RCDATA/RAWTEXT-style parsing, can be emitted into Markdown as raw HTML.

Examples of affected input include:

Text produced from entity-decoded input such as <script>...</script>
Text inside elements like <title>, <textarea>, <noscript> (when parsed as raw text), and <plaintext>

This is distinct from actual <script> or <style> elements in the DOM. Those are already dropped by default in to_markdown() unless html_passthrough=True.

Proof of Concept

General case

from justhtml import JustHTML

doc = JustHTML("<p>&lt;img src=x onerror=alert(1)&gt;</p>", fragment=True)

print(doc.to_html())
print()
print(doc.to_markdown())

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`justhtml`	all versions	1.12.0`pip install --upgrade 'justhtml==1.12.0'`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for justhtml, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update justhtml to 1.12.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-3rcm-vjrc-p45j is resolved across your whole dependency graph.
Workarounds
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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-3rcm-vjrc-p45j can be triaged on real exposure rather than presence alone.

Tailored to GHSA-3rcm-vjrc-p45j. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

## Summary `to_markdown()` does not sufficiently escape text content that looks like HTML. As a result, untrusted input that is safe in `to_html()` can become raw HTML in Markdown output. This is not specific to tokenizer raw-text states like `<title>`, `<noscript>`, or `<plaintext>`, although those states can trigger the behavior. The root cause is broader: Markdown text serialization leaves angle brackets unescaped in text nodes. ## Details When converting a parsed document to Markdown, text nodes are escaped for a small set of Markdown metacharacters, but HTML-significant characters suc

O3 Security · Impact-Aware SCA

Is GHSA-3rcm-vjrc-p45j in your dependencies?

O3 Security finds GHSA-3rcm-vjrc-p45j across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

Scan my dependencies How O3 SCA works