Next.js Vulnerable to HTTP Request Smuggling
Next.js is a React framework that can provide building blocks to create web applications. Prior to 13.5.1, an inconsistent interpretation of a crafted HTTP request meant that requests are treated as both a single request, and two separate requests by Next.js, leading to desynchronized responses. This led to a response queue poisoning vulnerability in the affected Next.js versions. For a request to be exploitable, the affected route also had to be making use of the [rewrites](https://nextjs.org/docs/app/api-reference/next-config-js/rewrites) feature in Next.js. The vulnerability is resolved in Next.js `13.5.1` and newer.
- Published
- May 14, 2024
- Updated
- Jun 17, 2026
- EPSS
- 1.2% · 67th percentile
- CWE
- CWE-444
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Report tools
Action score
30
Monitor
Low priority for now.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 1.2%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · GitHub_M
- 7.5
- NVD has not scored this yet; the score shown is the CNA’s.
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| vercel | next.js | cpe:2.3:a:vercel:next.js |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- vercel next.js13.4.0 and later · before 13.5.1
Versions reported by the vendor
Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.
vercel next.js
- >= 13.4.0, < 13.5.1affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| npm | next | from 13.4.0 · before 13.5.1 | 13.5.1 |
Same product
vercel: all recordsOther highest-scoring records for the same primary product.
- CVE-2025-29927Authorization Bypass in Next.js Middleware66This week
- CVE-2024-46982Cache Poisoning in next.js48Plan
- CVE-2021-43803Unexpected server crash in Next.js43Plan
- CVE-2025-55183An information leak vulnerability exists in specific configurations of React Server Components versions 19.0.0, 19.0.1 19.1.0, 19.1.1, 19.1.40Plan
- CVE-2026-75604Next.js: Unauthenticated Remote Code Execution on windows-hosted servers37Monitor
- CVE-2026-44578Next.js: Server-side request forgery in applications using WebSocket upgrades35Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| npm:next | 13.5.1 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
- CVE-2025-49826415 days apartNext.js DoS vulnerability via cache poisoning30Monitor
- CVE-2025-49005415 days apartNext.js cache poisoning due to omission of Vary header14Monitor
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- high · data or configuration can be modified
- Availability
- none
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- High
- Availability impact
- None
Weakness class (CWE)
CWE-444 · Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
ATT&CK techniques
—
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Vendor advisories and official records. Exploit/PoC links are deliberately left out.