CVE-2022-31109 is a high-severity (CVSS 7.2) Cross-site Scripting (XSS) vulnerability in laminas/laminas-diactoros. A fix is available for laminas/laminas-diactoros — see the affected versions and patch details below.
HTTP Host Header Attack Vulnerability in laminas-diactoros
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2022-31109.
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.
How urgent is this, really
CVE-2022-31109 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,333 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
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 is a PHP package containing implementations of the PSR-7 HTTP message interfaces and PSR-17 HTTP message factory interfaces. Applications that use Diactoros, and are either not behind a proxy, or can be accessed via untrusted proxies, can potentially have the host, protocol, and/or port of a Laminas\Diactoros\Uri instance associated with the incoming server request modified to reflect values from X-Forwarded-* headers. Such changes can potentially lead to XSS attacks (if a fully-qualified URL is used in links) and/or URL poisoning. Since the X-Forwarded-* headers do have valid use cases, particularly in clustered environments using a load balancer, the library offers mitigation measures only in the v2 releases, as doing otherwise would break these use cases immediately. Users of v2 releases from 2.11.1 can provide an additional argument to Laminas\Diactoros\ServerRequestFactory::fromGlobals() in the form of a Laminas\Diactoros\RequestFilter\RequestFilterInterface instance, including the shipped Laminas\Diactoros\RequestFilter\NoOpRequestFilter implementation which ignores the X-Forwarded-* headers. Starting in version 3.0, the library will reverse behavior to use the NoOpRequestFilter by default, and require users to opt-in to X-Forwarded-* header usage via a configured Laminas\Diactoros\RequestFilter\LegacyXForwardedHeaderFilter instance. Users are advised to upgrade to version 2.11.1 or later to resolve this issue. Users unable to upgrade may configure web servers to reject X-Forwarded-* headers at the web server level.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | laminas/laminas-diactoros | all versions | 2.11.1composer require laminas/laminas-diactoros:^2.11.1 |
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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update laminas/laminas-diactoros to 2.11.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2022-31109 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2022-31109 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2022-31109. 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-2022-31109 in your dependencies?
O3 Security finds CVE-2022-31109 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.