CVE-2021-27405 is a medium-severity (CVSS 4.3) Uncontrolled Resource Consumption vulnerability in @progfay/scrapbox-parser. O3 Security confirms whether CVE-2021-27405 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Regular expression Denial of Service in @progfay/scrapbox-parser
Real-World Exposure
@progfay/scrapbox-parser📦@progfay/scrapbox-parserReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm packages — download data is not available via public APIs for these ecosystems.
Description
Impact
A Regular expression Denial of Service flaw was found in the @progfay/scrapbox-parser package before 6.0.3, 7.0.2 for Node.js. The attacker that is able to be parsed a specially crafted text may cause the application to consume an excessive amount of CPU.
Patches
Upgrade to version 6.0.3, 7.0.2 or later.
Workarounds
Avoid to parse text with a lot of [ chars.
References
- https://github.com/progfay/scrapbox-parser/pull/519
- https://github.com/progfay/scrapbox-parser/pull/539
- https://github.com/progfay/scrapbox-parser/pull/540
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=2021-27405
- https://snyk.io/vuln/SNYK-JS-PROGFAYSCRAPBOXPARSER-1076803
For more information
If you have any questions or comments about this advisory:
- Open an issue in github.com/progfay/scrapbox-parser
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @progfay/scrapbox-parser | all versions | 6.0.3 |
| 📦npm | @progfay/scrapbox-parser | ≥ 7.0.0&&< 7.0.2 | 7.0.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @progfay/scrapbox-parser. 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 @progfay/scrapbox-parser to 6.0.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-27405 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-2021-27405 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-2021-27405. 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-2021-27405 in your dependencies?
O3 detects CVE-2021-27405 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.