GHSA-223j-4rm8-mrmf — next
GHSA-223j-4rm8-mrmf is a Information Exposure vulnerability in next. A fix is available for next — see the affected versions and patch details below.
Next.js may leak x-middleware-subrequest-id to external hosts
Exploitation Status
No confirmed exploitation observed yet
- 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 GHSA-223j-4rm8-mrmf.
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.
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.
nextnpmDescription
Summary
In the process of remediating CVE-2025-29927, we looked at other possible exploits of Middleware. We independently verified this low severity vulnerability in parallel with two reports from independent researchers.
Learn more here.
Credit
Thank you to Jinseo Kim kjsman and RyotaK (GMO Flatt Security Inc.) with takumi-san.ai for the responsible disclosure. These researchers were awarded as part of our bug bounty program.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | next | ≥ 12.3.5&&< 12.3.6 | 12.3.6npm install next@12.3.6 |
| 📦npm | next | ≥ 13.5.9&&< 13.5.10 | 13.5.10npm install next@13.5.10 |
| 📦npm | next | ≥ 14.2.25&&< 14.2.26 | 14.2.26npm install next@14.2.26 |
| 📦npm | next | ≥ 15.2.3&&< 15.2.4 | 15.2.4npm install next@15.2.4 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for next, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update next to 12.3.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-223j-4rm8-mrmf 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 GHSA-223j-4rm8-mrmf can be triaged on real exposure rather than presence alone.
Tailored to GHSA-223j-4rm8-mrmf. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-223j-4rm8-mrmf in your dependencies?
O3 Security finds GHSA-223j-4rm8-mrmf across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.