GHSA-26hh-7cqf-hhc6 CVE-2026-45109
Next.js has a Middleware / Proxy bypass in App Router applications via segment-prefetch routes - Incomplete Fix Follow-Up
- Severity
- 7.5 / 10
- High · CVSS 3.1
- Exploit chance (EPSS)
- 0.60%
- Chance of exploitation in the next 30 days. Higher than 48.80% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-288 Authentication Bypass Using an Alternate Path or Channel
- Fix
15.5.18- Upgrade next to this version or later
Description
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 versions
npm
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
next npm → 15.5.18
- npm
npm install next@15.5.18- yarn
yarn add next@15.5.18- pnpm
pnpm add next@15.5.18
Severity breakdown
CVSS 3.1 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
Weakness
CWE-288: Authentication Bypass Using an Alternate Path or Channel
The product requires authentication, but the product has an alternate path or channel that does not require authentication.
How to prevent it
- Architecture and Design: Funnel all access through a single choke point to simplify how users can access a resource. For every access, perform a check to determine if the user has permissions to access the resource.
References
Advisories
Packages
Other links
- github.com/vercel/next.js/security/advisories/GHSA-267c-6grr-h53f
- github.com/vercel/next.js/security/advisories/GHSA-26hh-7cqf-hhc6
- github.com/vercel/next.js/releases/tag/v15.5.18
- github.com/vercel/next.js/releases/tag/v16.2.6
- access.redhat.com/errata/RHSA-2026:34608
- access.redhat.com/errata/RHSA-2026:37272
- access.redhat.com/errata/RHSA-2026:40974
- access.redhat.com/errata/RHSA-2026:54435
- access.redhat.com/security/cve/CVE-2026-45109
- bugzilla.redhat.com/show_bug.cgi
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-45109.json
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-673q-mjm6-r5xr Next.js: Unauthenticated Remote Code Execution in `use cache` functions returning typed arrays | Critical | Also affects next |
| GHSA-2464-fhr4-w9xw Next.js: Unauthenticated Remote Code Execution in Image Optimization API when SVG files are used | Critical | Also affects next |
| GHSA-p3m5-59mp-jv5r Next.js: Denial of Service in App Router using Server Actions | High | Also affects next |
| GHSA-3w37-wq28-93x7 Next.js: Pending `use cache` fill can leak Draft Mode content into regular responses and persisted pages | Medium | Also affects next |
| GHSA-4jqv-mc3x-m676 Next.js has cache poisoning of SSG and ISR pages in self-hosted applications | Medium | Also affects next |
| GHSA-39w2-rjm5-chcv Next.js has information disclosure in development server's Model Context Protocol endpoint | Medium | Also affects next |
| GHSA-f87g-xv8r-7p7x Next.js has information disclosure in App Router metadata image routes via dynamicParams bypass | Medium | Also affects next |
| GHSA-mcj8-r9mp-w47p Next.js has cache poisoning in SSG/ISR rendering that leads to cross-user content substitution and persistent denial of service | Medium | Also affects next |
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