CVE-2026-44581

Next.js: Cross-site scripting in App Router applications using CSP nonces

MEDIUM
4.7
CVSS Score
Published: May 13, 2026 at 05:07 PM UTC
Updated: October 26, 2026 at 02:10 PM UTC
1 product affected across 1 vendorNext.js

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Severity
MEDIUM4.7
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

Description

Next.js is a React framework for building full-stack web applications. From 13.4.0 to before 15.5.16 and 16.2.5, App Router applications that rely on CSP nonces can be vulnerable to stored cross-site scripting when deployed behind shared caches. In affected versions, malformed nonce values derived from request headers could be reflected into rendered HTML in an unsafe way, allowing an attacker to poison cached responses and cause script execution for later visitors. This vulnerability is fixed in 15.5.16 and 16.2.5.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

13.4.0 ≤ v < 15.5.1616.0.0 ≤ v < 16.2.5
Affected range stops below 15.5.16, so it looks safe — our inference, not a vendor statement
Affected range stops below 16.2.5, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (1)

x_refsource_CONFIRMMitigationVendor Advisory
Source: cverecord
https://github.com/vercel/next.js/security/advisories/GHSA-ffhc-5mcf-pf4q

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

4.7MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-79

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