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Full vulnerability report · 2026
CVE-2026-94543High confidence

Next.js: Cache poisoning of SSG and ISR pages in self-hosted Next.js applications

vercel · next.js

Official source article: GitHub GHSA-4JQV-MC3X-M676 ↗. Check the applicable product and release in the original source.

6.3MediumCVSS 4.0
Recommended action
Patch only the product branches with a verified fix

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority. Verified remediation exists for at least one product or source, but 20 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityMediumOperational priority:Medium, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 0.29% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict the affected network interface to trusted sources where business-safe.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs vercel next.js and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: As exposure requiresRemediation target: Within 365 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Cross-source reconciliation

Remediation availability differs by product scope

Verified remediation exists for at least one product or source, but 20 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Open-source package ranges4 source-attributed ranges

These OSV and GitHub advisory ranges apply only to the named package and ecosystem. A listed fixed version is not a universal product patch or proof that an update is installed.

Ecosystem and packageAffected rangeFirst fixed versionEvidence
npmnext>= 15.0.0, < 15.5.2715.5.27GitHub advisory ↗upstream repository advisory · 7 Oct 2026
npmnext>= 16.0.0, < 16.3.816.3.8GitHub advisory ↗upstream repository advisory · 7 Oct 2026
npmnextSEMVER: introduced 15.0.0; fixed 15.5.2715.5.27OSV record ↗aggregator derived · 7 Oct 2026
npmnextSEMVER: introduced 16.0.0; fixed 16.3.816.3.8OSV record ↗aggregator derived · 7 Oct 2026
Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current
CVE-2026-94543 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitynext: Next.js: Response cache poisoning via improper route binding
20 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • firefox as a component of Red Hat Enterprise Linux 10
  • firefox.src as a component of Red Hat Enterprise Linux 10
  • thunderbird as a component of Red Hat Enterprise Linux 10
  • thunderbird.src as a component of Red Hat Enterprise Linux 10
  • firefox as a component of Red Hat Enterprise Linux 7
  • firefox.src as a component of Red Hat Enterprise Linux 7
  • firefox as a component of Red Hat Enterprise Linux 8
  • firefox.src as a component of Red Hat Enterprise Linux 8
  • thunderbird as a component of Red Hat Enterprise Linux 8
  • thunderbird.src as a component of Red Hat Enterprise Linux 8
  • firefox as a component of Red Hat Enterprise Linux 9
  • firefox-x11 as a component of Red Hat Enterprise Linux 9
Summary
A flaw was found in Next.js. In self-hosted applications using the Pages Router with static generation or Incremental Static Regeneration (ISR), response cache entries are not sufficiently bound to their source route. A remote attacker can exploit this issue by sending crafted requests to replace a page's cache entry with content from a different route. This results in response cache poisoning, causing the application to serve incorrect content to subsequent visitors.
Remediation
Fix deferred
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-91670

No EUVD known-exploited evidence

Next.js is a React framework for building full-stack web applications. From 15.0.0 until 15.5.27 and 16.3.8, self-hosted applications using the Pages Router with statically generated or Incremental Static Regeneration pages can key a response cache entry without sufficiently binding it to the source route. A request can replace one page's cache entry with content from a different route, causing the affected page to serve incorrect content to every visitor until revalidation. Applications deployed on Vercel are not affected. This issue is fixed in versions 15.5.27 and 16.3.8.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
6.3 · CVSS 4.0
Advisory evidence
No linked advisory details stored yet
Recommended actionPatch only the product branches with a verified fix

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority. Verified remediation exists for at least one product or source, but 20 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
01

What, why and how

Next.js is a React framework for building full-stack web applications. From 15.0.0 until 15.5.27 and 16.3.8, self-hosted applications using the Pages Router with statically generated or Incremental Static Regeneration pages can key a response cache entry without sufficiently binding it to the source route. A request can replace one page's cache entry with content from a different route, causing the affected page to serve incorrect content to every visitor until revalidation. Applications deployed on Vercel are not affected. This issue is fixed in versions 15.5.27 and 16.3.8.

What

Next.js is a React framework for building full-stack web applications. From 15.0.0 until 15.5.27 and 16.3.8, self-hosted applications using the Pages Router with statically generated or Incremental Static Regeneration pages can key a response cache entry without sufficiently binding it to the source route. A request can replace one page's cache entry with content from a different route, causing the affected page to serve incorrect content to every visitor until revalidation. Applications deployed on Vercel are not affected. This issue is fixed in versions 15.5.27 and 16.3.8.

Why

The code uses a cache that contains sensitive information, but the cache can be read by an actor outside of the intended control sphere.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

Next.js is a React framework for building full-stack web applications. From 15.0.0 until 15.5.27 and 16.3.8, self-hosted applications using the Pages Router with statically generated or Incremental Static Regeneration pages can key a response cache entry without sufficiently binding it to the source route. A request can replace one page's cache entry with content from a different route, causing the affected page to serve incorrect content to every visitor until revalidation. Applications deployed on Vercel are not affected. This issue is fixed in versions 15.5.27 and 16.3.8.

Why

The code uses a cache that contains sensitive information, but the cache can be read by an actor outside of the intended control sphere.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Use of Cache Containing Sensitive Information → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
High: exploitation depends on specific conditions
Security boundary
Not a CVSS 4.0 base metric
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-524 ↗

CWE-524: Use of Cache Containing Sensitive Information. The code uses a cache that contains sensitive information, but the cache can be read by an actor outside of the intended control sphere.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

Common Vulnerability Scoring System 4.0: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACHighAttack complexity: Successful exploitation depends on specific conditions outside the attacker's direct control.ATPresentAttack requirements: A particular deployment or execution condition must be present.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.VCNoneVulnerable-system confidentiality: No direct loss is represented by this metric.VINoneVulnerable-system integrity: No direct loss is represented by this metric.VALowVulnerable-system availability: A successful attack can cause a limited loss.SCNoneSubsequent-system confidentiality: No direct loss is represented by this metric.SINoneSubsequent-system integrity: No direct loss is represented by this metric.SANoneSubsequent-system availability: No direct loss is represented by this metric.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedCWE-524
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-91670Official EUVD mapping

Next.js is a React framework for building full-stack web applications. From 15.0.0 until 15.5.27 and 16.3.8, self-hosted applications using the Pages Router with statically generated or Incremental Static Regeneration pages can key a response cache entry without sufficiently binding it to the source route. A request can replace one page's cache entry with content from a different route, causing the affected page to serve incorrect content to every visitor until revalidation. Applications deployed on Vercel are not affected. This issue is fixed in versions 15.5.27 and 16.3.8.

Official EUVD record ↗
BSI · German · WID-SEC-2026-3699Vercel Next.js: Mehrere Schwachstellen

Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Vercel Next.js ausnutzen, um vertrauliche Informationen offenzulegen, Sicherheitsmaßnahmen zu umgehen, Daten zu manipulieren oder Denial-of-Service-Zustände auszulösen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20261007Security Bulletin 7 Oct 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 7 Oct 2026, published on 7 October 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-036540Vercel, Inc. (旧 Zeit, Inc.)のNext.jsにおける重要な情報を含むキャッシュの使用に関する脆弱性

Next.jsは、フルスタックのウェブアプリケーションを構築するためのReactフレームワークです。バージョン15.0.0から15.5.27および16.3.8までの間にリリースされたPages Routerを使用し、静的生成または増分的静的再生成（Incremental Static Regeneration）ページを含むセルフホスト型アプリケーションでは、レスポンスキャッシュのエントリがソースルートに十分に結び付けられないままキー付けされる可能性があります。これにより、一部のページのキャッシュエントリが別のルートのコンテンツで置き換えられ、影響を受けたページが検証されるまで、すべての訪問者に誤ったコンテンツが提供されてしまいます。なお、Vercelにデプロイされたアプリケーションには影響がありません。この問題はバージョン15.5.27および16.3.8で修正されています。

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Fix availability varies by product
Affected
Fixed
An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Action
Use the product-specific evidence above. Patch only products with a verified fixed release, and keep every affected or under-investigation state without a matching fix in the remediation queue.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
Official vendor articles3 stored documents

Linked articles are downloaded and versioned as source evidence. A CVE mention or approved update relationship does not, by itself, verify a fix for every product branch.

04

Evidence and provenance

Published 2 Oct 2026 · Last source change 6 Oct 2026, 16:31 UTC · CWE-524 · Use of Cache Containing Sensitive Information

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-10-03
European sourceENISA EUVD · EUVD-2026-91670
Product sourceVendor CSAF · Red Hat Product Security
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. BlackTree coverageBlackTree article coverage changed from 1 BlackTree article to 1 BlackTree article.
    Before
    1 BlackTree article
    After
    1 BlackTree article
    BlackTree editorial ↗
  2. ENISA EUVD mappingEUVD-2026-91670 was added to the official ENISA EUVD mapping for this CVE.
    Before
    not recorded
    After
    {"euvdId":"EUVD-2026-91670"}
    ENISA EUVD ↗
  3. Vendor guidanceAuthoritative vendor guidance changed: added patch: github.com/52c94abdd2ea5f416f5e8353ea8a2edd3fe311b8; added patch: github.com/719e4c67d6e92df60246f95e1d96e2dd60789a52; 2 further additions.
    Before
    no authoritative guidance recorded
    After
    patch: github.com/52c94abdd2ea5f416f5e8353ea8a2edd3fe311b8 · patch: github.com/719e4c67d6e92df60246f95e1d96e2dd60789a52 · remediation: github.com/52c94abdd2ea5f416f5e8353ea8a2edd3fe311b8 · 1 more references
    security-advisories@github.com ↗
  4. Affected versionsThe structured affected or fixed version information changed.
    Before
    next.js: >= 15.0.0, < 15.5.27, >= 16.0.0, < 16.3.8 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    next.js: >= 15.0.0, < 15.5.27, >= 16.0.0, < 16.3.8 · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
    CNA ↗
  5. Remediation statusRemediation status changed from Awaiting fix to Patch available.
    Before
    Awaiting fix
    After
    Patch available
    security-advisories@github.com ↗
  6. Vendor guidanceAuthoritative vendor guidance changed: removed remediation: wid.cert-bund.de/securityadvisory?name=WID-SEC-2026-3699.
    Before
    remediation: wid.cert-bund.de/securityadvisory?name=WID-SEC-2026-3699
    After
    no authoritative guidance recorded
    CNA ↗
  7. Affected versionsThe structured affected or fixed version information changed.
    Before
    Vercel Next.js <16.3.8; Vercel Next.js <15.5.27 · Fixed: No fixed version is explicitly recorded in this authority advisory.
    After
    next.js: >= 15.0.0, < 15.5.27, >= 16.0.0, < 16.3.8 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    CNA ↗
  8. SeveritySeverity changed from Unknown to Medium.
    Before
    Unknown
    After
    Medium
    CNA ↗
  9. CVSS scoreCVSS score changed from not recorded to 6.3 (CVSS 4.0 · CNA · CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N).
    Before
    not recorded
    After
    6.3 (CVSS 4.0 · CNA · CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N)
    CNA ↗
  10. BlackTree coverageBlackTree article coverage changed from no BlackTree article to 1 BlackTree article.
    Before
    no BlackTree article
    After
    1 BlackTree article
    BlackTree editorial ↗
  11. Catalogue recordCVE added to the BlackTree catalogue.
    Official national cybersecurity authority ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2026-91670↗Vendor CSAF · Red Hat Product Security↗CVE authority or vendor reference · GitHub GHSA-4JQV-MC3X-M676↗Patch or update reference↗Patch or update reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-94543 · cve.blacktree.nl