How severe is GHSA-39q2-94rc-95cp?

No CVSS score has been assigned to GHSA-39q2-94rc-95cp yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-39q2-94rc-95cp?

GHSA-39q2-94rc-95cp affects the following packages: dompurify (npm). Ecosystems affected: npm.

How do I fix GHSA-39q2-94rc-95cp?

Update dompurify to 3.4.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-39q2-94rc-95cp is resolved across your whole dependency graph.

How do I detect GHSA-39q2-94rc-95cp in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for dompurify. 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-39q2-94rc-95cp 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-39q2-94rc-95cp?

O3 pinpoints whether GHSA-39q2-94rc-95cp 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-39q2-94rc-95cp actively exploited in the wild?

No public exploit code has been indexed for GHSA-39q2-94rc-95cp 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-39q2-94rc-95cp published, and has it been updated?

GHSA-39q2-94rc-95cp was published on April 16, 2026 and was last updated on April 16, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm

GHSA-39q2-94rc-95cp

DOMPurify's ADD_TAGS function form bypasses FORBID_TAGS due to short-circuit evaluation

Published

Apr 16, 2026

Updated

Apr 16, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Blast Radius

1 pkg affected

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

dompurifynpm

48.6Mdownloads / week

Description

Summary

In src/purify.ts:1117-1123, ADD_TAGS as a function (via EXTRA_ELEMENT_HANDLING.tagCheck) bypasses FORBID_TAGS due to short-circuit evaluation.

The condition:

!(tagCheck(tagName)) && (!ALLOWED_TAGS[tagName] || FORBID_TAGS[tagName])

When tagCheck(tagName) returns true, the entire condition is false and the element is kept — FORBID_TAGS[tagName] is never evaluated.

Inconsistency

This contradicts the attribute-side pattern at line 1214 where FORBID_ATTR explicitly wins first:

if (FORBID_ATTR[lcName]) { continue; }

For tags, FORBID should also take precedence over ADD.

Impact

Applications using both ADD_TAGS as a function and FORBID_TAGS simultaneously get unexpected behavior — forbidden tags are allowed through. Config-dependent but a genuine logic inconsistency.

Suggested Fix

Check FORBID_TAGS before tagCheck:

if (FORBID_TAGS[tagName]) { /* remove */ }
else if (tagCheck(tagName) || ALLOWED_TAGS[tagName]) { /* keep */ }

Affected Version

v3.3.3 (commit 883ac15)

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`dompurify`	all versions	3.4.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for dompurify. 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 dompurify to 3.4.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-39q2-94rc-95cp 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-39q2-94rc-95cp 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-39q2-94rc-95cp. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

## Summary In `src/purify.ts:1117-1123`, `ADD_TAGS` as a function (via `EXTRA_ELEMENT_HANDLING.tagCheck`) bypasses `FORBID_TAGS` due to short-circuit evaluation. The condition: ``` !(tagCheck(tagName)) && (!ALLOWED_TAGS[tagName] || FORBID_TAGS[tagName]) ``` When `tagCheck(tagName)` returns `true`, the entire condition is `false` and the element is kept — `FORBID_TAGS[tagName]` is never evaluated. ## Inconsistency This contradicts the attribute-side pattern at line 1214 where `FORBID_ATTR` explicitly wins first: ``` if (FORBID_ATTR[lcName]) { continue; } ``` For tags, FORBID should also take

O3 Security · Impact-Aware SCA

Is GHSA-39q2-94rc-95cp in your dependencies?

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