Next.js has a Middleware / Proxy bypass in App Router applications via segment-prefetch routes - Incomplete Fix Follow-UpGHSA-26hh-7cqf-hhc6
HIGHGHSA-26hh-7cqf-hhc6 is a high-severity (CVSS 7.5) CWE-288 vulnerability in next. A fix is available for next — see the affected versions and patch details below.
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 GHSA-26hh-7cqf-hhc6.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
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
Impact
It was found that the fix addressing CVE-2026-44575 did not apply to middleware.ts with Turbopack. Refer to CVE-2026-44575 for further details.
References
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | next | ≥ 15.2.0&&< 15.5.18 | 15.5.18npm install next@15.5.18 |
| 📦npm | next | ≥ 16.0.0&&< 16.2.6 | 16.2.6npm install next@16.2.6 |
Affected Products
next.jsvercelDetection & 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 15.5.18 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-26hh-7cqf-hhc6 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.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
This Important information disclosure flaw in Next.js allows a remote unauthenticated attacker to bypass a prior security fix when applications utilize `middleware.ts` with Turbopack. This bypass undermines intended access controls, potentially leading to the exposure of sensitive information in affected Red Hat AMQ…
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.Source: Red Hat security advisory for GHSA-26hh-7cqf-hhc6 (CC BY 4.0)
| Product | Fixed in | Advisory |
|---|---|---|
| Streams for Apache Kafka 2.9.4 | next | RHSA-2026:34608 |
| Streams for Apache Kafka 3.2.1 | next | RHSA-2026:54435 |
| Red Hat Trusted Artifact Signer 1.3 | rhtas/rekor-search-ui-rhel9:1783958622 | RHSA-2026:40974 |
| Red Hat Trusted Artifact Signer 1.4 | rhtas/rekor-search-ui-rhel9:1783327185 | RHSA-2026:37272 |
Frequently Asked Questions
Is GHSA-26hh-7cqf-hhc6 in your dependencies?
Find it across npm, including transitive dependencies.