Security readout for executives and security teams
Plain-English summary
A flaw in Next.js lets attackers slip past the security check that guards protected pages. By crafting specific query parameters, an unauthenticated or low-privilege user can view content that middleware was supposed to block. The visible URL looks normal, so the bypass may not be obvious in logs. Vercel has released fixed versions that customers should install promptly.
Executive priority
Treat as a high-priority patch this sprint for any customer-facing or internal Next.js app that relies on middleware for access control. Impact is confidentiality and integrity of gated content; no denial-of-service. Coordinate with application owners to schedule upgrade windows within days, not weeks, and confirm no legacy branches remain on affected versions.
Technical view
Next.js versions 15.4.0 through 15.5.15 and 16.0.0 through 16.2.4 mishandle dynamic route parameters when middleware runs. A crafted query string can change the dynamic route value the page renders while the visible path stays unchanged, causing the middleware authorization check to evaluate a different route than what is served. This enables authorization bypass (CWE-288) and visible/actual mismatch (CWE-551). Fixed in 15.5.16 and 16.2.5.
Likely exposure
Any Next.js application on 15.4.0–15.5.15 or 16.0.0–16.2.4 that uses middleware to gate access to dynamic routes (e.g., /users/[id], /admin/[section]). Deployments on Vercel, self-hosted Node, or container images built on affected releases are all in scope. Static-only or non-middleware-protected apps are not affected.
Exploitation context
No CISA KEV listing and no public reports of active exploitation are cited in the source bundle. CVSS 8.1 (AV:N/AC:L/PR:L/UI:N/C:H/I:H) indicates a network-reachable, low-complexity bypass requiring only low privileges and no user interaction. The GitHub Security Advisory GHSA-492v-c6pp-mqqv provides the authoritative technical description; Red Hat has issued vendor errata RHSA-2026:37272 and RHSA-2026:34608.
Researcher notes
Root cause is a mismatch between the route value middleware evaluates and the route the page ultimately renders when specific query parameters are supplied. This is a classic CWE-551 visible/actual behavior divergence layered on a CWE-288 authentication bypass. Defense-in-depth guidance: never rely on middleware alone for authorization decisions on dynamic routes; re-check identity and resource ownership inside the page, route handler, or server component. No public PoC or KEV entry cited as of 2026-07-10.
Mitigation direction
- Upgrade Next.js to 15.5.16 (15.x branch) or 16.2.5 (16.x branch) across all environments.
- Apply Red Hat errata RHSA-2026:37272 and RHSA-2026:34608 on affected RHEL-based deployments.
- Rebuild and redeploy container images and serverless bundles that pin an affected Next.js version.
- Re-enforce authorization inside page/route handlers as defense-in-depth, not only in middleware.
- Review WAF or edge rules to alert on unusual query parameters targeting dynamic route paths.
Validation and detection
- Inventory Next.js versions via package.json, lockfiles, and SBOMs across repos and build artifacts.
- Confirm upgraded version reports 15.5.16 or 16.2.5 in production runtime logs or /_next assets.
- Review middleware.ts/matcher config to identify dynamic routes gated only by middleware.
- Test protected dynamic routes with variant query strings to verify middleware still enforces authorization.
- Check access logs for anomalous query parameters against dynamic route paths since 2026-05-13.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
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-288: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. 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.
Open ATT&CK lookupCWE-551: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. 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.
Open ATT&CK lookupPrivilege behavior lookup
The CVE wording references privilege impact, so privilege escalation and authorization behavior review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-44574 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 8.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
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.
SSVC decision data
CVSS vector scores
2 official scoresWe 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.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N2.85.2GitHub_MCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N2.85.2redhat-SADPVulnerability scoring details
Base CVSS 3.1 score
8.1HighVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Base CVSS 3.1 score
8.1HighVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- ADP timelineredhat-SADP
Made public.
- CVE publishedCVE Program
The CVE record was published.
- ADP timelineredhat-SADP
Reported to Red Hat.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
- 2026-05-13T18:02:21.088Z: Reported to Red Hat.
- 2026-05-13T16:56:06.008Z: Made public.
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/vercel/next.js/security/advisories/GHSA-492v-c6pp-mqqvCVE reference, GitHub_M · x_refsource_CONFIRM
- https://access.redhat.com/security/cve/CVE-2026-44574CVE reference, redhat-SADP · vdb-entry, x_refsource_REDHAT
- RHBZ#2477207CVE reference, redhat-SADP · issue-tracking, x_refsource_REDHAT
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-44574.jsonCVE reference, redhat-SADP · x_sadp-csaf-vex
- https://access.redhat.com/errata/RHSA-2026:37272CVE reference, redhat-SADP · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:34608CVE reference, redhat-SADP · vendor-advisory, x_refsource_REDHAT
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Authentication Bypass Using an Alternate Path or Channel
Authentication Bypass Using an Alternate Path or Channel represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Incorrect Behavior Order: Authorization Before Parsing and Canonicalization
Incorrect Behavior Order: Authorization Before Parsing and Canonicalization represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.