Update dependency next to v15.5.18 [SECURITY]

[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence
next (source)	15.5.9 → 15.5.18

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Next.js HTTP request deserialization can lead to DoS when using insecure React Server Components

GHSA-h25m-26qc-wcjf

More information

Details

A vulnerability affects certain React Server Components packages for versions 19.0.x, 19.1.x, and 19.2.x and frameworks that use the affected packages, including Next.js 13.x, 14.x, 15.x, and 16.x using the App Router. The issue is tracked upstream as CVE-2026-23864.

A specially crafted HTTP request can be sent to any App Router Server Function endpoint that, when deserialized, may trigger excessive CPU usage, out-of-memory exceptions, or server crashes. This can result in denial of service in unpatched environments.

Severity

• CVSS Score: 7.5 / 10 (High)
• Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

• https://github.com/facebook/react/security/advisories/GHSA-83fc-fqcc-2hmg
• https://github.com/vercel/next.js/security/advisories/GHSA-h25m-26qc-wcjf
• https://nvd.nist.gov/vuln/detail/CVE-2026-23864
• https://vercel.com/changelog/summary-of-cve-2026-23864
• https://github.com/advisories/GHSA-h25m-26qc-wcjf

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

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Next.js self-hosted applications vulnerable to DoS via Image Optimizer remotePatterns configuration

CVE-2025-59471 / GHSA-9g9p-9gw9-jx7f

More information

Details

A DoS vulnerability exists in self-hosted Next.js applications that have remotePatterns configured for the Image Optimizer. The image optimization endpoint (/_next/image) loads external images entirely into memory without enforcing a maximum size limit, allowing an attacker to cause out-of-memory conditions by requesting optimization of arbitrarily large images. This vulnerability requires that remotePatterns is configured to allow image optimization from external domains and that the attacker can serve or control a large image on an allowed domain.

Strongly consider upgrading to 15.5.10 and 16.1.5 to reduce risk and prevent availability issues in Next applications.

Severity

• CVSS Score: 5.9 / 10 (Medium)
• Vector String: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

References

• https://github.com/vercel/next.js/security/advisories/GHSA-9g9p-9gw9-jx7f
• https://nvd.nist.gov/vuln/detail/CVE-2025-59471
• https://github.com/vercel/next.js/commit/500ec83743639addceaede95e95913398975156c
• https://github.com/vercel/next.js/commit/e5b834d208fe0edf64aa26b5d76dcf6a176500ec
• https://github.com/vercel/next.js/releases/tag/v15.5.10
• https://github.com/vercel/next.js/releases/tag/v16.1.5
• https://github.com/advisories/GHSA-9g9p-9gw9-jx7f

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

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Next.js: HTTP request smuggling in rewrites

CVE-2026-29057 / GHSA-ggv3-7p47-pfv8

More information

Details

Summary

When Next.js rewrites proxy traffic to an external backend, a crafted DELETE/OPTIONS request using Transfer-Encoding: chunked could trigger request boundary disagreement between the proxy and backend. This could allow request smuggling through rewritten routes.

Impact

An attacker could smuggle a second request to unintended backend routes (for example, internal/admin endpoints), bypassing assumptions that only the configured rewrite destination/path is reachable. This does not impact applications hosted on providers that handle rewrites at the CDN level, such as Vercel.

Patches

The vulnerability originated in an upstream library vendored by Next.js. It is fixed by updating that dependency’s behavior so content-length: 0 is added only when both content-length and transfer-encoding are absent, and transfer-encoding is no longer removed in that code path.

Workarounds

If upgrade is not immediately possible:

• Block chunked DELETE/OPTIONS requests on rewritten routes at your edge/proxy.
• Enforce authentication/authorization on backend routes per our security guidance.

Severity

• CVSS Score: 6.3 / 10 (Medium)
• Vector String: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

References

• https://github.com/vercel/next.js/security/advisories/GHSA-ggv3-7p47-pfv8
• https://github.com/vercel/next.js/commit/dc98c04f376c6a1df76ec3e0a2d07edf4abdabd6
• https://github.com/vercel/next.js/releases/tag/v15.5.13
• https://github.com/vercel/next.js/releases/tag/v16.1.7
• https://nvd.nist.gov/vuln/detail/CVE-2026-29057
• https://github.com/advisories/GHSA-ggv3-7p47-pfv8

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

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Next.js: Unbounded next/image disk cache growth can exhaust storage

CVE-2026-27980 / GHSA-3x4c-7xq6-9pq8

More information

Details

Summary

The default Next.js image optimization disk cache (/_next/image) did not have a configurable upper bound, allowing unbounded cache growth.

Impact

An attacker could generate many unique image-optimization variants and exhaust disk space, causing denial of service. Note that this does not impact platforms that have their own image optimization capabilities, such as Vercel.

Patches

Fixed by adding an LRU-backed disk cache with images.maximumDiskCacheSize, including eviction of least-recently-used entries when the limit is exceeded. Setting maximumDiskCacheSize: 0 disables disk caching.

Workarounds

If upgrade is not immediately possible:

• Periodically clean .next/cache/images.
• Reduce variant cardinality (e.g., tighten values for images.localPatterns, images.remotePatterns, and images.qualities)

Severity

• CVSS Score: 6.9 / 10 (Medium)
• Vector String: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

References

• https://github.com/vercel/next.js/security/advisories/GHSA-3x4c-7xq6-9pq8
• https://github.com/vercel/next.js/commit/39eb8e0ac498b48855a0430fbf4c22276a73b4bd
• https://github.com/vercel/next.js/releases/tag/v16.1.7
• https://nvd.nist.gov/vuln/detail/CVE-2026-27980
• https://github.com/advisories/GHSA-3x4c-7xq6-9pq8

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

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Next.js has a Denial of Service with Server Components

GHSA-q4gf-8mx6-v5v3

More information

Details

A vulnerability affects certain React Server Components packages for versions 19.x and frameworks that use the affected packages, including Next.js 13.x, 14.x, 15.x, and 16.x using the App Router. The issue is tracked upstream as CVE-2026-23869. You can read more about this advisory our this changelog.

A specially crafted HTTP request can be sent to any App Router Server Function endpoint that, when deserialized, may trigger excessive CPU usage. This can result in denial of service in unpatched environments.

Severity

• CVSS Score: 7.5 / 10 (High)
• Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

• https://github.com/vercel/next.js/security/advisories/GHSA-q4gf-8mx6-v5v3
• https://vercel.com/changelog/summary-of-cve-2026-23869
• https://github.com/advisories/GHSA-q4gf-8mx6-v5v3

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

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Next.js has a Middleware / Proxy bypass through dynamic route parameter injection

CVE-2026-44574 / GHSA-492v-c6pp-mqqv

More information

Details

Impact

Applications that rely on middleware to protect dynamic routes can be vulnerable to authorization bypass. In affected deployments, specially crafted query parameters can alter the dynamic route value seen by the page while leaving the visible path unchanged, which can allow protected content to be rendered without passing the expected middleware check.

Fix

We now only honor internal route-parameter normalization in trusted routing flows and ignore externally supplied parameter encodings that should never have been accepted from ordinary requests.

Workarounds

If you cannot upgrade immediately, enforce authorization in route or page logic instead of relying solely on middleware path matching.

Severity

• CVSS Score: 8.1 / 10 (High)
• Vector String: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

References

• https://github.com/vercel/next.js/security/advisories/GHSA-492v-c6pp-mqqv
• https://github.com/vercel/next.js/releases/tag/v15.5.16
• https://github.com/vercel/next.js/releases/tag/v16.2.5
• https://github.com/advisories/GHSA-492v-c6pp-mqqv

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

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Next.js has a Middleware / Proxy bypass in App Router applications via segment-prefetch routes

CVE-2026-44575 / GHSA-267c-6grr-h53f

More information

Details

Impact

App Router applications that rely on middleware or proxy-based checks for authorization can allow unauthorized access through transport-specific route variants used for segment prefetching. In affected configurations, specially crafted .rsc and segment-prefetch URLs can resolve to the same page without being matched by the intended middleware rule, which can allow protected content to be reached without the expected authorization check.

Fix

We now include App Router transport variants when generating middleware matchers, so middleware protections are applied consistently to those requests as well as to the normal page URL.

Workarounds

If you cannot upgrade immediately, enforce authorization in the underlying route or page logic instead of relying solely on middleware.

Severity

• CVSS Score: 7.5 / 10 (High)
• Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

References

• https://github.com/vercel/next.js/security/advisories/GHSA-267c-6grr-h53f
• https://github.com/vercel/next.js/releases/tag/v15.5.16
• https://github.com/vercel/next.js/releases/tag/v16.2.5
• https://github.com/advisories/GHSA-267c-6grr-h53f

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

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Next.js has a Middleware / Proxy bypass in App Router applications via segment-prefetch routes - Incomplete Fix Follow-Up

CVE-2026-45109 / GHSA-26hh-7cqf-hhc6

More information

Details

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

• CVE CVE-2026-44575

Severity

• CVSS Score: 7.5 / 10 (High)
• Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

References

• https://github.com/vercel/next.js/security/advisories/GHSA-267c-6grr-h53f
• https://github.com/vercel/next.js/security/advisories/GHSA-26hh-7cqf-hhc6
• https://github.com/vercel/next.js/releases/tag/v15.5.18
• https://github.com/vercel/next.js/releases/tag/v16.2.6
• https://github.com/advisories/GHSA-26hh-7cqf-hhc6

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

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Next.js vulnerable to Denial of Service via connection exhaustion in applications using Cache Components

CVE-2026-44579 / GHSA-mg66-mrh9-m8jx

More information

Details

Impact

Applications using Partial Prerendering through the Cache Components feature can be vulnerable to connection exhaustion through crafted POST requests to a server action. In affected configurations, a malicious request can trigger a request-body handling deadlock that leaves connections open for an extended period, consuming file descriptors and server capacity until legitimate users are denied service.

Fix

We now treat the header used for resuming Partial Prerendered requests as an internal-only header and strip it from untrusted incoming requests. This header should never be accepted directly from external clients.

Workarounds

If you cannot upgrade immediately, block requests that would be handled by Next.js if they contain the Next-Resume header at the edge.

Severity

• CVSS Score: 7.5 / 10 (High)
• Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

• https://github.com/vercel/next.js/security/advisories/GHSA-mg66-mrh9-m8jx
• https://github.com/vercel/next.js/releases/tag/v15.5.16
• https://github.com/vercel/next.js/releases/tag/v16.2.5
• https://github.com/advisories/GHSA-mg66-mrh9-m8jx

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

---

Release Notes

vercel/next.js (next)

v15.5.18

Compare Source

v15.5.16

Compare Source

v15.5.15

Compare Source

Please refer the following changelogs for more information about this security release:

https://vercel.com/changelog/summary-of-cve-2026-23869

v15.5.14

Compare Source

v15.5.13

Compare Source

v15.5.12

Compare Source

[!NOTE]
This release is backporting bug fixes. It does not include all pending features/changes on canary.

• fix unlock in publish-native

This is a re-release of v15.5.11 applying the turbopack changes.

v15.5.11

Compare Source

[!NOTE]
This release is backporting bug fixes. It does not include all pending features/changes on canary.

Core Changes

• Tracing: Fix memory leak in span map (#​85529)
• fix: ensure LRU cache items have minimum size of 1 to prevent unbounded growth (#​89134)
• Turbopack: fix NFT tracing of sharp 0.34 (#​82340)
• Turbopack: support pattern into exports field (#​82757)
• NFT tracing fixes (#​84155 and #​85323)
• Turbopack: validate CSS without computing all paths (#​83810)
• feat: implement LRU cache with invocation ID scoping for minimal mode response cache (#​89129)

Credits

Huge thanks to @​timneutkens, @​mischnic, @​ztanner, and @​wyattjoh for helping!

v15.5.10

Compare Source

Please refer the following changelogs for more information about this security release:

• https://vercel.com/changelog/summaries-of-cve-2025-59471-and-cve-2025-59472
• https://vercel.com/changelog/summary-of-cve-2026-23864

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Status	Category	Percentage	Covered / Total
🔵	Lines	1.32%	135 / 10207
🔵	Statements	1.32%	135 / 10207
🔵	Functions	48.81%	103 / 211
🔵	Branches	51.78%	116 / 224

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