How severe is GHSA-h6mq-3cj6-h738?

GHSA-h6mq-3cj6-h738 has a CVSS score of 3.1/10, rated LOW. Review your exposure and patch according to your risk tolerance.

Which packages are affected by GHSA-h6mq-3cj6-h738?

GHSA-h6mq-3cj6-h738 affects the following packages: showdown (npm). Ecosystems affected: npm.

How do I fix GHSA-h6mq-3cj6-h738?

Update showdown to 1.9.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-h6mq-3cj6-h738 is resolved across your whole dependency graph.

How do I detect GHSA-h6mq-3cj6-h738 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for showdown. 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.

How do I mitigate GHSA-h6mq-3cj6-h738 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-h6mq-3cj6-h738?

O3 pinpoints whether GHSA-h6mq-3cj6-h738 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-h6mq-3cj6-h738 actively exploited in the wild?

No public exploit code has been indexed for GHSA-h6mq-3cj6-h738 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.

When was GHSA-h6mq-3cj6-h738 published, and has it been updated?

GHSA-h6mq-3cj6-h738 was published on September 3, 2020 and was last updated on October 1, 2021. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

GHSA-h6mq-3cj6-h738: Reverse Tabnabbing in showdown (Low 3.1)

Blast Radius

1 pkg affected

Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.

showdownnpm

1.4Mdownloads / week

Description

Versions of showdown prior to 1.9.1 are vulnerable to Reverse Tabnabbing. The package uses target='_blank' in anchor tags, allowing attackers to access window.opener for the original page when opening links. This is commonly used for phishing attacks.

Recommendation

Upgrade to version 1.9.1 or later.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`showdown`	all versions	1.9.1

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for showdown. 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.
Fix
Update showdown to 1.9.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-h6mq-3cj6-h738 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 pinpoints whether GHSA-h6mq-3cj6-h738 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-h6mq-3cj6-h738. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

Versions of `showdown` prior to 1.9.1 are vulnerable to [Reverse Tabnabbing](https://www.owasp.org/index.php/Reverse_Tabnabbing). The package uses `target='_blank'` in anchor tags, allowing attackers to access `window.opener` for the original page when opening links. This is commonly used for phishing attacks. ## Recommendation Upgrade to version 1.9.1 or later.

O3 Security · Impact-Aware SCA

Is GHSA-h6mq-3cj6-h738 in your dependencies?

O3 detects GHSA-h6mq-3cj6-h738 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works

GHSA-h6mq-3cj6-h738