CVE-2023-29530
HIGHLaminas Diactoros vulnerable to HTTP Multiline Header Termination
EPSS Exploitation Probability
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.
Blast Radius
laminas/laminas-diactoros🐘laminas/laminas-diactoros🐘laminas/laminas-diactoros🐘laminas/laminas-diactoros🐘laminas/laminas-diactoros🐘laminas/laminas-diactoros🐘laminas/laminas-diactoros🐘laminas/laminas-diactorosReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
Laminas Diactoros provides PSR HTTP Message implementations. In versions 2.18.0 and prior, 2.19.0, 2.20.0, 2.21.0, 2.22.0, 2.23.0, 2.24.0, and 2.25.0, users who create HTTP requests or responses using laminas/laminas-diactoros, when providing a newline at the start or end of a header key or value, can cause an invalid message. This can lead to denial of service vectors or application errors. The problem has been patched in following versions 2.18.1, 2.19.1, 2.20.1, 2.21.1, 2.22.1, 2.23.1, 2.24.1, and 2.25.1. As a workaround, validate HTTP header keys and/or values, and if using user-supplied values, filter them to strip off leading or trailing newline characters before calling withHeader().
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | laminas/laminas-diactoros | all versions | 2.18.1 |
| 🐘Packagist | laminas/laminas-diactoros | ≥ 2.19.0&&< 2.19.1 | 2.19.1 |
| 🐘Packagist | laminas/laminas-diactoros | ≥ 2.20.0&&< 2.20.1 | 2.20.1 |
| 🐘Packagist | laminas/laminas-diactoros | ≥ 2.21.0&&< 2.21.1 | 2.21.1 |
| 🐘Packagist | laminas/laminas-diactoros | ≥ 2.22.0&&< 2.22.1 | 2.22.1 |
| 🐘Packagist | laminas/laminas-diactoros | ≥ 2.23.0&&< 2.23.1 | 2.23.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for laminas/laminas-diactoros. 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 laminas/laminas-diactoros to 2.18.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-29530 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-2023-29530 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-2023-29530. 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-2023-29530 in your dependencies?
O3 detects CVE-2023-29530 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.