CVE-2026-55451
Fix: locize/gettext-converter@df90c3bCVE-2026-55451 is a security vulnerability in gettext-converter. O3 Security confirms whether CVE-2026-55451 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
gettext-converter: Prototype pollution in js2i18next() via crafted translation keys
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
gettext-converternpmDescription
Impact
js2i18next() is vulnerable to prototype pollution. When converting translations, it splits nested keys on the key separator (default ##) and uses each segment as a dynamic object key while building the output object. A key whose segment is __proto__ (e.g. __proto__##gcPolluted) causes the converter to resolve Object.prototype as the nested write target and assign the translated value onto it, polluting Object.prototype for the whole runtime.
Any application that converts translation data (PO / i18next JS objects) originating from an untrusted or user-controlled source is affected. Prototype pollution can lead to denial of service and, depending on the surrounding application, may enable further attacks.
Patches
Fixed in [email protected]. Key segments equal to __proto__, constructor, or prototype are now rejected before being used as dynamic object keys.
Workarounds
Upgrade to 1.3.3. If upgrading is not immediately possible, sanitize/validate translation keys before passing them to js2i18next() and reject any key whose ##-separated segments include __proto__, constructor, or prototype.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | gettext-converter | all versions | 1.3.3 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for gettext-converter. 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 gettext-converter to 1.3.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-55451 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 CVE-2026-55451 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 CVE-2026-55451. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-55451 in your dependencies?
O3 detects CVE-2026-55451 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.