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CVE Record

CVE-2026-44578: Next.js: Server-side request forgery in applications using WebSocket upgrades

Next.js is a React framework for building full-stack web applications. From 13.4.13 to before 15.5.16 and 16.2.5, self-hosted applications using the built-in Node.js server can be vulnerable to server-side request forgery through crafted WebSocket upgrade requests. An attacker can cause the server to proxy requests to arbitrary internal or external destinations, which may expose internal services or cloud metadata endpoints. Vercel-hosted deployments are not affected. This vulnerability is fixed in 15.5.16 and 16.2.5.

HighCVSS 8.6Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

Internet-facing, self-hosted Next.js applications may be tricked into contacting systems that attackers cannot reach directly. This could expose internal services or cloud metadata. Vercel-hosted deployments are not affected.

Executive priority

Prioritize prompt remediation for internet-facing self-hosted deployments, especially those able to reach cloud metadata or sensitive internal services. Treat confirmed affected systems as high priority. Vercel-hosted applications do not require remediation for this CVE.

Technical view

CVE-2026-44578 is a CWE-918 SSRF affecting specified Next.js versions using the built-in Node.js server. Crafted WebSocket upgrade requests can make the server proxy requests to arbitrary internal or external destinations. CVSS 3.1 is 8.6, reflecting unauthenticated, low-complexity network access and potentially high confidentiality impact.

Likely exposure

Exposure requires a self-hosted Next.js application using the built-in Node.js server and an affected version: 13.4.13–15.5.15 or 16.0.0–16.2.4. Publicly reachable WebSocket upgrade handling increases concern. Vercel-hosted deployments are explicitly unaffected.

Exploitation context

The supplied record is not listed in CISA KEV, and the source bundle provides no evidence of active exploitation. Exploitation is described as unauthenticated and low complexity, but actual reachability depends on deployment architecture, request handling, and network access from the application server.

Researcher notes

The vulnerability crosses a trust boundary because WebSocket upgrade handling can become a server-side proxy. The CVSS scope-change and confidentiality-high ratings align with possible access to protected destinations. The bundle does not establish data theft, public proof-of-concept availability, active exploitation, or integrity and availability impact.

Mitigation direction

  • Upgrade affected 13–15 deployments to an applicable fixed release, including 15.5.16, after compatibility testing.
  • Upgrade affected 16.x deployments to Next.js 16.2.5 or later.
  • Confirm deployments use patched dependencies in production, not merely updated lockfiles or development environments.
  • If upgrading is delayed, consult the vendor advisory for supported interim mitigations.

Validation and detection

  • Inventory self-hosted Next.js versions and identify deployments using the built-in Node.js server.
  • Separate Vercel-hosted deployments from self-hosted infrastructure when determining exposure.
  • Verify deployed runtime packages report Next.js 15.5.16, 16.2.5, or a later applicable release.
  • Review WebSocket upgrade telemetry for unusual requests or connections toward internal services and metadata endpoints.
  • Confirm network controls limit unnecessary access from application servers to sensitive internal and cloud metadata services.
Prepared
Confidence
high
Sources
4

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · medium confidence lookup

CWE-918: Information exposure and cloud metadata lookup

Information exposure and SSRF weaknesses can make discovery, cloud metadata, and credential material review relevant. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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description · low confidence lookup

Cloud metadata behavior lookup

The CVE wording references SSRF or metadata access, so cloud discovery and credential material review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2026-44578 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
High
CVSS
8.6 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

2CVSS vectors
5Timeline events
2ADP providers
9Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: yesTechnical Impact: partial

CVSS vector scores

2 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
8.6CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N3.94GitHub_M
8.6CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N3.94redhat-SADP

Vulnerability scoring details

Base CVSS 3.1 score

8.6High
CVSS 3.1 vector shape for CVE-2026-44578Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. ADP timelineredhat-SADP

    Made public.

  3. CVE publishedCVE Program

    The CVE record was published.

  4. ADP timelineredhat-SADP

    Reported to Red Hat.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
redhat-SADPNext.js: Next.js: Server-Side Request Forgery via crafted WebSocket upgrade requests
other:Red Hat severity ratingcvssV3_1
  • 2026-05-13T18:01:13.729Z: Reported to Red Hat.
  • 2026-05-13T17:01:38.942Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
vercelnext.js>= 16.0.0, < 16.2.5, >= 13.4.13, < 15.5.16Listed
Weakness

CWE details

CWE-918

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-918 · source CWE mapping

Server-Side Request Forgery (SSRF)

Server-Side Request Forgery (SSRF) represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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